When trees are uprooted and the land left bare, what happened to the rain water?​

Answers

Answer 1

Answer:

when trees are cut down, the bare surfaces left behind absorb more heat than the forest they replaced. And that heat helps draw air upward, pulling moist air in from nearby forested land that increases rainfall in the immediate area.


Related Questions

If an animal has radial symmetry, what phylum is it classified to be?

A) Porifera
B) Platyhelminthes
C) Rotifera
D) Cnidaria

Answers

Answer:

D-Cnidaria

Explanation:

took the test

Compare how fresh and marine fish overcome problems

Answers

Answer:

the ciliated epithelium tissue helps to collect the ovum why?

suggest how lack of oxygen could affect the operation of the cell membrane of the motor neuron ​

Answers

Answer:

Oxygen in the blood is required for function of neurons to fire constantly and be in action to transmit information.

Lack of oxygen causes disruption of mitochondrial respiration in motor neurons, disruption of mitochondrial activity, mitochondrial ATP synthesis, defective mitochondrial transport, imbalance in mitochondrial potential ultimately causing atrophy of macular motor neurons in action organs as legs and hands.

This leads to loss of activity of these motor neurons and message passing activity to motor organs eventually. This leads to decrease in functioning or atrophy of motor organs.

Hope its helpful!

Please mark me as brainlist.

Answer:

Oxygen in the blood is required for function of neurons to fire constantly and be in action to transmit information.

Lack of oxygen causes disruption of mitochondrial respiration in motor neurons, disruption of mitochondrial activity, mitochondrial ATP synthesis, defective mitochondrial transport, imbalance in mitochondrial potential ultimately causing atrophy of macular motor neurons in action organs as legs and hands.

This leads to loss of activity of these motor neurons and message passing activity to motor organs eventually. This leads to decrease in functioning or atrophy of motor organs.

Explanation:

Which synaptic connection would be most affected by the presence of a GABA antagonist in the cerebellum

Answers

The central nervous system (your brain and spinal cord) would be most affected by GABA antagonist.

What is GABA antagonist?In the neurological system, neurotransmitters act as chemical messengers.Neurons communicate with one another to transfer signals along the neurological systems, carrying messages.They may, for instance, send a message from your brain to your hand telling you to avoid danger or from your hand to your brain informing you that a pot is hot.GABA stops some nerve transmissions or signals since it is an inhibitory neurotransmitter.It stops neurons from being stimulated, which is how it works.This indicates that a neuron doesn't act on a message it receives along the way, preventing the message from being passed to other neurons. Functions:When a neuron receives messages, known as "action potentials," the message is transmitted to another neuron through a sequence of stages.However, GABA is present in between 30 and 40 percent of neurons.The GABAergic neurons are those. GABA is released into the synapses where the message is expected to be carried on when GABAergic neurons receive a message.The action potential's likelihood of spreading to neighboring neurons is decreased as a result of the release of GABA. Even while GABA activity only lasts for a few milliseconds, it has a big impact.It induces a soothing effect in the brain.This procedure enables the integration of sensory information in the spinal cord, enabling your nervous system to process and organize information coming from your eyes, ears, nose, and mouth.

Learn more about GABA antagonist here:

brainly.com/question/13652336

#SPJ4

how asthma is caused i just need a short answer

Answers

Answer:

These include:

•having an allergy-related condition, such as eczema, a food allergy or hay fever – these are known as atopic conditions

••having a family history of asthma or atopic conditions

having had bronchiolitis – a common childhood lung infection

••exposure to tobacco smoke as a child

your mother smoking during pregnancy

being born prematurely (before 37 weeks) or with a low birth weight

Answer:

your mother smoking during pregnancy

What is another
way that producers
convert energy,
besides
photosynthesis?
A. chemosynthesis
B. decomposition
C. cellular respiration

Answers

Answer:

A

Explanation:

Because chemosynthesis is the biological conversion of one or more carbon-containing molecules and nutrients into organic matter using the oxidation of inorganic compounds or ferrous ions as a source of energy, rather than sunlight, as in photosynthesis.  So it can only be this because decomposition is something decaying and cellular respiration is the process by which organisms combine oxygen with foodstuff molecules, diverting the chemical energy in these substances into life-sustaining activities and discarding, as waste products, carbon dioxide and water.

what’s a non property of water?

Answers

Answer:

-it dissolves molecules in the air

-it becomes denser when it freezes.

Hormones are chemical molecules produced by endocrine glands. One such endocrine gland is the thyroid gland, which synthesizes the thyroid hormone, which in turn affects the heart muscles. Which two statements describe the probable reason for the function of the hormone?
The cells in the heart have specific receptors that allow for the intake of hormones.
The heart and the endocrine glands have the exact same types of cells.
All cells make the same types of hormones.
Thyroid hormones show their effect on the heart by means of specialized cells.
Thyroid cells and cardiac cells have different DNA.

Answers

The correct statements are

Statement(1) : The cells in the heart have specific receptors that allow for the intake of hormones.

Statement(4) : Thyroid hormones show their effect on the heart by means of specialized cells.

What are hormones?

Hormones are chemicals that coordinate many bodily processes by sending information to your organs, skin, muscles, and other tissues through your blood. Your body receives these messages that instruct it when and what to do. Your life and health depend on hormones.

Your endocrine system is composed primarily of the glands and tissues that produce and secrete hormones. Numerous physiological functions are regulated by hormones.

What are thyroid hormones?

The key hormone in charge of regulating how quickly your body's metabolism works is the thyroid hormone. Thyroid hormone is essential for baby brain development. Thyroid hormone is produced and released by your thyroid, a little gland in the shape of a butterfly that is tucked under the skin at the front of your neck. Your endocrine system contains it.

What are endocrine glands?

The network of glands in your body known as the endocrine system produces the hormones needed for cells to communicate with one another. They are in charge of practically every cell, organ, and bodily process. The endocrine system is made up of several glands.

To learn more about thyroid glands and thyroid hormones:

https://brainly.com/question/10533967

#SPJ4

The two statements are: The cells in the heart have specific receptors that allow for the intake of hormones and Thyroid hormones show their effect on the heart by means of specialized cells.

What are hormones?

Hormones are chemical messengers produced by endocrine glands that regulate various physiological processes and behaviors in the body. They are secreted into the bloodstream and carried to target cells or organs where they exert their effects by binding to specific receptors. Hormones play a crucial role in maintaining homeostasis, coordinating growth and development, regulating metabolism, controlling reproductive functions, and influencing mood and behavior.

Different endocrine glands produce different types of hormones, each with its specific functions and target tissues. Examples of hormones include insulin, cortisol, estrogen, testosterone, and thyroid hormone. The precise balance and regulation of hormones are essential for the proper functioning of the body and maintaining overall health and well-being.

Learn more about hormones, here:

https://brainly.com/question/30527782

#SPJ5

A rock resting high on a cliff is an example of an object with
what type of energy? (2 points)
Kinetic energy because it is doing work
O Kinetic energy because it has the ability to do work
Potential energy because it is doing work
Potential energy because it has the ability to do work?

Answers

Answer:

Potential energy because it has the ability to do work

Explanation:

Kinetic energy is when an object is doing work, and potential energy is when an object has the potential to get kinetic energy either due to it's position or molecular composition. In this case since the rock is resting high on a cliff, it has a bunch of potential energy, due to it's position, because gravity. If it were to fall of the cliff, it would then convert that potential energy to kinetic energy, but at that moment, since it's resting, it's only potential energy, because it has the potential to convert into kinetic energy. So the correct answer is: Potential energy because it has the ability to do work

The goal of a statement of purpose is:​

Answers

Answer:

A statement of purpose's goal is to convince someone that you should be admitted to the program or be awarded a position.

Answer:

A statement of purpose's goal is to convince someone that you should be admitted to the program or be awarded a position.

How to prevent diseases that spread through mosquitoes?

Answers

Use insect repellents any time you are outdoors.
Wear long-sleeved clothing.
Schedule outdoor activities to avoid the hours from dusk to dawn during peak mosquito season.
Repair damaged window and door screens.
Remove standing water from the areas around your home.

The virus introduced to the island in 1982 that reduced the wolf population is an example of ________.

Answers

The virus introduced to the island in 1982 that reduced the wolf population is an example of a density dependent factor.

In ecology, a density-dependent factor, also known as a regulatory factor, is any force that modifies the size of a population of living creatures in response to population density.

Because of their propensity to maintain population densities, density-dependent factors are also known as regulating factors.

Population size and a density-dependent factor's level of control are correlated, therefore an increase in population will increase the influence of the limitation. Density-dependent factors involve biotic factors such as availability of food , predation, competition,  parasitism and disease.

Learn more about density dependent factor here :

https://brainly.com/question/23579465

#SPJ4

Glycogen - Starch - Polysaccharide - Saturated fat A. Carbohydrate polymer B. Hard at room temperature C. Animal carbohydrates D. Plant carbohydrates

Answers

Polysaccharide - A) Carbohydrate polymer

Starch - D) Plant carbohydrate

Glycogen. - C) Animal carbohydrate

Saturated fat. - B) Hard at room temperature

What are carbohydrates?

Carbohydrates (also called carbs) are a type of macronutrient found in certain foods and drinks. Sugars, starches and fiber are carbohydrates.

Carbohydrates are often referred to as saccharides and form ring structures.

To know more about carbohydrate :

https://brainly.com/question/19874109

#SPJ4

Glycogen - (C) Animal carbohydrate

Starch - (D) Plant carbohydrate

Polysaccharide - (A) Carbohydrate polymer

Saturated fat - (B) Hard at room temperature

1. Glycogen -  Animal carbohydrate

Animal starch is a type of starch termed glycogen that is present in animal tissue.

2. Starch -  Plant carbohydrate

The primary form of stored carbohydrates in plants is starch.

3. Polysaccharide - Carbohydrate polymer

long-chain polymeric carbohydrates made up of glycosidic connections holding monosaccharide molecules together.

4. Saturated fat - Hard at room temperature

Saturated fats are tightly packed fats that are solid at room temperature because their chemical structures don't contain double bonds.

Learn more about polysaccharide here:

https://brainly.com/question/730920

#SPJ4

Biology question on human digestive system​

Answers

Answer:

X : A) To absorb amino acids

Y : B) To secrete enzymes

Answer:

X) C. to transport fats

Y) C. to secrete enzymes

Explanation:

    The epithelium or "Y" is responsible for the absorption of nutrients, and the protection of the human body from microbial infections.

    The lacteal or "X" absorbs dietary fats in the villi of the small intestine. It absorbs and transports large molecules, fats, and lipids in the digestive system.

Hope this helped :]

How are channel and carrier proteins different?

Select all that apply.


Channel proteins move substances across the membrane at a much faster rate than carrier proteins.


Channel proteins allow all types of molecules to pass through the membrane, while carrier proteins are specific to what they transport.


Carrier proteins can allow much larger substances to cross the membrane than channel proteins do.


Carrier proteins undergo a shape change as they move substances across the membrane, while channel proteins do not.

Answers

Answer:

Carrier proteins undergo a shape change as they move substances across the membrane, while channel proteins do not. Channel proteins move substances across the membrane at a much faster rate than carrier proteins. Carrier proteins can allow much larger substances to cross the membrane than channel proteins do.
Its the Last one
Hope it helps!

The largest reservoir of phosphorus in the biosphere is

Answers

Answer:Ocean sediments

Explanation:

An owl eats it's pray while or in large pieces. summarize what is found in an owl pellet an why is regurgitated

Answers

Pellets are the portions of a bird's diet that have not been digested and are regurgitated. Examples of pellets include hair and bones . Pellets are produced by a wide variety of bird species, including but not limited to birds of prey, crows, and even sparrows.

Owl pellets consist of indigestible elements of their prey, such as bones, fur, claws, and teeth. However, they perform another crucial function for the owl. Regurgitating pellets, which travel through the bird's gullet on the way back up, scrub and clean the digestive tract, eliminating infections and maintaining the bird's health. Those who raise birds of prey like owls and falcons can utilize the pellets to determine the health of their birds.

Prey animals, such as field mice, have learnt to avoid the pellets since they are infectious agents. However, certain owl pellet pathogens, such as Salmonella, can potentially infect humans.

Learn more about owl pellets here :

https://brainly.com/question/4851583

#SPJ4

Collections of sympathetic postganglionic axons, parasympathetic preganglionic axons, and some visceral sensory axons that provide complex innervation to target organs are known as ______ plexuses.

Answers

Collections of sympathetic postganglionic axons, parasympathetic preganglionic axons, and some visceral sensory axons that provide complex innervation to target organs are known as Autonomic Plexuses.

The solar plexus is the most important autonomic plexus and affords innervation to a couple of abdominal and pelvic organs. The superior mesenteric plexus consists of the superior mesenteric ganglia and is positioned across the advanced mesenteric artery.

The 5 autonomic plexuses include the Celiac plexus (additionally referred to as the sun plexus): This plexus sits in the back of your stomach and innervates organs of your stomach. Auerbach's plexus: This plexus innervates your gut and functions as part of your digestive device.

A nerve plexus is a community of intersecting nerves; a couple of nerve plexuses exist in the body. Nerve plexuses are composed of afferent and efferent fibers that stand up from the merging of the anterior rami of spinal nerves and blood vessels.

Learn more about Autonomic  Plexuses here https://brainly.com/question/10519370

#SPJ4

The diversification of reptiles facilitated by the evolution of the reptilian egg is a good example of Group of answer choices parallel evolution. devolution adaptive radiation.

Answers

The diversification of reptiles facilitated by the evolution of the reptilian egg is a good example of adaptive radiation.

What is adaptive radiation?

A rapid growth in the number of species sharing a common ancestor that is characterized by high ecological and morphological variation is known as adaptive radiation. It is fueled by organisms' ability to adapt to novel ecological situations.

The formation of their scaly skin, which contains the protein keratin and waxy lipids, limiting water loss from the skin, was one of the major adaptations that allowed reptiles to live on land. Because of this occlusive skin, reptiles and amphibians both use their lungs to breathe rather than their skin for respiration. The phenomenon of adaptive radiation was first observed by Darwin. During the Mesozoic era, the age of reptiles ( dinosaurs), mammals were small, generalized, and rare.

Learn more about adaptive radiation here:

brainly.com/question/12862756

#SPJ4

If a diploid cell has 12 chromosomes in prophase i, how many chromatids will the cell have at the completion of anaphase i and anaphase ii?

#1
always 12

#2
12 and 6

#3
36 and 24

#4
24 and 12

Answers

4) 24 and 12

What happens during anaphase I and anaphase II stage?

One of the two cell divisions is meiosis. From a single parent cell, it generates four daughter cells. Each cell has half of the parent cell's chromosomes. Meiosis I and Meiosis II are the two primary mechanisms that cause meiosis. Four subdivisions make up each meiosis. In meiosis I, anaphase I takes place, and in meiosis II, anaphase II. The homologous chromosomes are pulled apart and moved to the opposite ends of the cell during anaphase I, whereas during anaphase II, the sister chromatids of each chromosome are separated and moved towards the poles. Additionally, anaphase I happens when a cell is in the diploid condition, but anaphase II happens when a cell is in haploid condition.

The cell has 12 chromosomes, after anaphase I stage each chromatid is considered a separate chromosome structure, hence there will be 24 chromosomes. After meiosis I is complete the number of chromosomes again become 12 because of the division of the nucleus.

At anaphase II, the sister chromatids are separated hence, the number of chromosomes remain 12.

Learn more about anaphase stage here:

https://brainly.com/question/2390199

#SPJ4

On the periodic table, electronegativity increases as we move from the left column to the right. What information does this give us?

A) Nitrogen is more likely than oxygen to form a chemical bond
B) Hydrogen and helium are equally likely to form a chemical bond
C) Fluorine and neon are equally likely to form a chemical bond
D) Oxygen is more likely than nitrogen to form a chemical bond

Answers

Answer:

I think answer a hope it is helpful

Consider a situation in which overharvesting causes the number of fish in a population to become drastically smaller, which causes genetic variation in that fish to decrease over a few generations. This is an example of: Group of answer choices

Answers

Answer:

bottleneck effect

Explanation:

A small child has albino characteristics, photophobia, frequent pyogenic infections, and her blood smear shows giant dark granules in her monocytes and granulocytes. What is the probable diagnosis

Answers

Chediak-Higashi syndrome is defined as the abnormal fusion of cytoplasmic lysozymes in granulocytes and occasionally monocytes.  This condition is associated with albino characteristics, photophobia, and frequent infections (as the granules are dysfunctional and cannot fight infection appropriately).

White blood cells are a part of the frame's immune gadget. They assist the body combat infection and other illnesses. forms of white blood cells are granulocytes (neutrophils, eosinophils, and basophils), monocytes, and lymphocytes (T cells and B cells).

A sort of immune mobile that has granules (small particles) with enzymes that might be launched at some stage in infections, allergies, and asthma. Neutrophils, eosinophils, and basophils are granulocytes. A granulocyte is a type of white blood cell.

Monocytes are a kind of white blood cells (leukocytes) that are living in your blood and tissues to discover and wreck germs (viruses, bacteria, fungi, and protozoa) and do away with inflamed cells. Monocytes call on other white blood cells to help deal with injury and save you from contamination.

Learn more about monocytes and granulocytes here https://brainly.com/question/10315797

#SPJ4

Which of the following is true regarding deductive reasoning but NOT inductive reasoning?


It begins with a theory.
It begins with a theory.

It is an open-ended approach.
It is an open-ended approach.

It begins with an observation.
It begins with an observation.

It results in a conclusion.

Answers

The following is true regarding deductive reasoning but NOT inductive reasoning it results in a conclusion. Thus, option "D" is correct.

What is deductive reasoning?

In deductive reasoning , the researcher begins with a theory and uses research to test the theory.

In the deductive approach, the theory must be tested through the collection of significant facts that prove the theory is true. In the inductive approach, the researcher does many observations and collects data. With this data, the researcher constructs a theory to explain these facts.

Thus, option "D" is correct since in In deductive reasoning , the researcher begins with a theory and uses research to test the theory.

To learn more about deductive reasoning click here:

https://brainly.com/question/16685989

#SPJ1

You would expect a cell with many chloroplasts to, secrete a lot of fats, make ATP, do photosynthesis, or store water?

Answers

Answer:

Cells with many chloroplast usually aids in the process of photolysis which is helpful in photosynthesis. so we can say that the more is the chloroplast in a plant cell the more is the rate of photosynthesis and ATP is made.

Gene got medicare before he turned 65 and enrolled into a medicare advantage plan. He calls in february the month before his 65th birthday and is unhappy with his current plan. On the date of the call, what can gene do about his coverage?.

Answers

On the date of the call, gene can wait to be 65 years old and prepare the necessary documentation, as medicare is by law to be integrated to people aged 65 and over.

How Old Are People Generally Eligible for Medicare?

If they are 65 years of age or older. Are on kidney dialysis or have had a kidney transplant. Are under 65 with certain disabilities.

With this information, we can conclude that Medicare is a program jointly funded by the federal and state governments to help pay for health care.

Learn more about medicare in brainly.com/question/14011571

#SPJ1

Elle wanted to test how temperature affects the rate of evaporation. She had
three setups:
Setup 1: Elle placed a container with 1 cup of water at room temperature
(25°C).
Setup 2: Elle placed a container with 1 cup of water in a warm room (45°C).
Setup 3: Elle placed a container with 1 cup of water in a cold room (0°C).
Which setup was the control?
A. There was no control.
B. Setup 1
C. Setup 2
D. Setup

Answers

Setup 1 was the control of this experiment designed by Elle to test how temperature affects the rate of evaporation. Thus, the correct option is B.

What is Evaporation?

Evaporation may be defined as a methodology where liquid transforms into a gas below the temperature at which it boils.

Setup 1 was the control because the room temperature (25°C) is an optimum temperature, where no chemical as well physical properties allow the substances to transform into another state.

Therefore, the correct option for this question is B.

To learn more about Temperature effects, refer to the link:

https://brainly.com/question/15885

#SPJ1

Which of the following is the source of energy for the water cycle?
A. volcanic eruptions
B. winds
C. gravity
D. the sun

Answers

D) The sun.

Sun causes the water to evaporate quickly depending upon the intensity of the sunlight.


The correct answer is D, the sun.

What type of cross is a mating between two individuals that are both heterozygous for the same two genes

Answers

Answer:

Dihybrid cross

Explanation:

Each ____ fragment of an antibody molecule contains the variable regions of a heavy and light chain which makes up a site which binds to an antigenic epitope. Group of answer choices

Answers

Each Immunoglobulin fragment of an antibody molecule contains the variable regions of a heavy and light chain which makes up a site that binds to an antigenic epitope.

A protein is made by means of B cells and plasma cells (varieties of white blood cells) and allows the body fight contamination.

A few immunoglobulins may be observed in better than regular quantities in patients with sure conditions or certain styles of cancer, including multiple myeloma and Waldenstrom macroglobulinemia.

Immunoglobulins are the antibodies produced clearly by the frame's immune system, which help combat infection and sickness. Intravenous immunoglobulin, or IVIg, is a remedy that combines immunoglobulins donated by using one-of-a-kind humans to deal with diverse situations.

Learn more about Immunoglobulins here: https://brainly.com/question/15382995

#SPJ4

Other Questions
A merry-go-round has a small box placed on it at a distance R' from its axis ofrotation. Initially (at time = 0), the merry-go-round is stationary. At time t = 0.0, aconstant torque of 6 Nm is applied to it, causing it to start rotating. As the merry-go-round spins faster, a point comes when the small box slides off of it. Given thefollowing data, calculate the time after it starts spinning, that the box will slip offthe disk. Assume that the merry-go-round is a solid disc. Write your answer inseconds.Mass of the merry-go-round (disk) = 30 kg.Radius of the merry-go-round = 3.1 mDistance from the axis where the box is placed = R = 1.4 mCoefficient of friction between merry-go-round and box: Static = 0.5, kinetic 136mm into cm and mm Explain the importance of collaborating with other members of the IEP team and parents/guardians. Include discussion regarding how this collaboration across settings and with many different collaborators promotes the well-being of students with disabilities. Which individual is responsible for ordering, preparing, and reviewing closing-related documents, such as the title policy and settlement statement Type of matter where all ofthe atoms that make up thematter are exactly the same A resident was restrained after refusing to take his medication. What right is being violated?. Estimate a daily total exercise time goal for each crew member on the top of each crew member's health tracker page. If you do not know the best target value, you can put down 100 minutes for now. You'll learn more about this value in another lesson. Americans may disagree about political issues and who should serve in leadership positions, but we share a similar ________________________ which promotes the protection of such values as liberty, equality, and the right to private property. Cell X has a resting potential of -80mV. If a ___________ open and causes the potential to change 10mV, the resulting potential will be ___________. Shortcutz hair salon offers inexpensive haircuts for $10. They create a marketing campaign extolling the cheap price while showing customers how expensive other salons are in comparison. The campaign encourages consumers shop around and compare prices. Shortcutz focuses solely on price and mentions little about the quality of its haircuts. Which type of psychological pricing communication does shortcutz use?. . population is of great importance in the economic development of Country Explain this statement with four point. in a mercantilism, which was ine purpose served by colines find x on the following figure What is f(-3) for thefunction f(a)=-2a?-5a+4? In reaction to the Tang infiltration into the Korean Peninsula, a. Japan declared war upon Korea. b. Japanese governmental power became more decentralized for a time. c. Shotoku Taishi made contacts with Tang rulers in order to adopt Chinese governing methods. d. relations between the Korean kingdoms and the Japanese rulers became estranged. e. Japan declared war upon Tang China. The fact that the Court has ruled that campaign contributions are a form of speech makes campaign finance regulation more difficult because brainstorm ideas brainstorm ideas for your house. think about devices, appliances, and building materials you want your house to have. in addition, these computer tools might help you brainstorm some ideas. this calculator gives you the average energy use of household appliances, so you can research energy-saving alternatives. this quiz can tell you what your carbon footprint is and how to reduce it in your home. consider turning some of the questions into energy solutions. for example, one of the questions is, do you turn off your faucets? if water supply is a concern in your region, perhaps faucets that turn off automatically might be an eco-friendly solution. this database provides information about air emissions rates in a region. search the zip code for the location you chose and select one of the electrical companies listed. then scroll down to see how much of the energy in this zip code comes from renewable and nuclear energy (a non-renewable, cleaner energy source) compared to fossil fuel sources (oil, coal, and gas). bar graphs compare the zip code's energy profile to the national average. write down your ideas for the house youll design. explain how those ideas can reduce carbon dioxide emissions and preserve natural diversity. What is the minimum number of users a remarketing list must have before being used with a Remarketing List for Search Ads campaign A vehicle comes to a stop 10.0 s after the brakes are applied. While the brakes were applied, the vehicle travelled a distance of75.0 m. If the vehicle's acceleration remained constant during the braking, what was the vehicle's initial speed? Is the random variable given in the accompanying table discrete or continuous? explain.