Why must an experiment have a control group?

Answers

Answer 1

Explanation:

The control group provides a baseline in the experiment. The variable that is being studied in the experiment is not changed or is limited to zero in the control group.


Related Questions

What family does the mushroom come from

Answers

The mushroom comes from the agaric family
they come from the agaric family

Explain how zooxanthellae have a symbiotic relationship with coral.

Answers

Answer:

Zooxanthellae and coral have a mutualistic, symbiotic relationship. Coral obtains oxygen and organic products from the algae that live within them. These algae also help the coral remove waste. The zooxanthellae obtains needed carbon dioxide and needed nutrients from the coral. The coral also provides the zooxanthellae with a protected habitat. Because both organisms derive a benefit from their relationship, it is considered mutualistic.

A symbiotic interaction benefits both the species. Corals and zooxanthellae shows a symbiotic relationship where zooxanthellae produce oxygen and corals perform photosynthesis.

What is Symbiotic relationship?

Symbiosis is a type of species interaction, it is any type of a close and long-term biological interaction which is between the two different biological organisms. Symbiotic relationships are mutualistic, commensalistic, or parasitic type. The organisms, are termed as symbiont.

The corals and the special cells of zooxanthellae have a mutualistic relationship. The corals provide the zooxanthellae with a protected surrounding environment and the compounds which they need for the process of photosynthesis. In return, the zooxanthellae produce oxygen for respiration and helps the coral species to remove waste materials.

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Describe the concept of natural selection, using the Galapagos finches as an example. Imagine you were trying to explain the concept to someone who did not know what it is.

Answers

Answer and Explanation:

Natural selection is the result of the phenotype-environment interaction which determines gene destiny in space and time, selecting beneficial alleles and increasing their frequency in the population. It is a consequence of the individual differential capability to reproduce and leave offspring. There must be also a genetic base called heritability. Natural selection involves interactions between individuals, the physical environment, and the biological environment.  

Natural selection results in adaptation, an increase of the aptitude phenotype.  In many cases, adaptations, resulting from natural selection, can be correlated to environmental factors or selective pressures applied by other organisms.

The selective agent is the environmental characteristic that determines the differential survival of the phenotypic classes.  

Some intraspecific phenotype variations follow a geographical distribution and can be correlated to changes in environmental conditions, such as temperature or humidity.  

Adaptive evolution refers to changes in the organism that lead to the evolution of the species and that are adaptive to certain conditions of the environment. Birds adapt to diverse ecological niches showing specialized beak forms to improve functions such as feeding, mating, defending, competing, and etcetera. These factors play an important role in beak shaping. Natural selection produces adaptive evolution.

During 1977 Daphne Major island went through an important drought, and many plant species produced few or no seeds during and after the event. The medium ground finch population, which is seed-feeder species, was hardly affected by this phenomenon. As seeds´ production dropped and the sizes of the extisting seeds were considerably smaller, the finch population declined drastically from about 1400 individuals to a few hundred in a period of two years, approximately. The fact is that the island weather controls plant species development, and thus, seeds availability as food for the birds. Years later after the drought, the finches population managed to recover but showing differences in the size of their beaks. Before the drought finches had a stubby beak and many years after recovering the average size of the beaks was larger than the beak size of the original population.  This difference in phenotype was due to the fact that during the drought, small seeds were very scarce, but large seeds with thick husks were still available. Small birds with small beaks starved because they were not able to open the husk and eat the interior of the seed. But those birds with bigger and stronger beaks were able to do so, and hence, managed to survive. The bird population adapted to the new environmental conditions and resource availability. Natural selection acted on the beak size, changing it.  

There are different kinds of natural selection, but in the present example, directional selection is operating.  

Directional selection increases the proportion of individuals with an extreme phenotypic trait, in this case, large beaks. This selection presents more frequently in those cases in which interactions between living organisms and the environment modify in the same direction.

Furthermore, beak size is not only related to feeding strategies, but also to reproduction. Female finches only mate with males that have the same beak size.

Which of the following is a prokaryote? Will award 25 points

Answers

The prokaryote in the picture is B

cockroaches are exposed to a pesticide, after 3 hours 95% of the insects are dead. what is the independent and dependent variable?

Answers

IV: Amount of pesticide
Independent variable is what can be changed

DV: Time of death how long it takes
What you can’t change

why can you not see the constellation that is in the suns house?

Answers

Answer:

If we could see the stars in the daytime, we would see the sun slowly wander ... constellation was conferred the title of "House of the sun," and in this ... And yet the Serpent Holder is not considered a member of the Zodiac.

Explanation:

2. Which one of the following is a reasonable measurement for the height of a
coconut palm tree?
a. 250 m
b. 25 m
C. 2.5 m
d. 0.25 m

Answers

The answer is (B),coconut Palm trees grow up to 30m so it’s (B)

In what organ of the human body would you find the amygdala?

Answers

It's The Brain!!!!!!!!!!!!!!!!!!!!!

Answer:The amygdala is an almond-shaped structure in the brain;

Explanation:

As with most other brain structures, you actually have two amygdalae (shown in red in the drawing here). Each amygdala is located close to the hippocampus, in the frontal portion of the temporal lobe.

how does a plant get water form the ground

Answers

Answer:

Plants absorb nutrients and water through their roots, but photosynthesis — the process by which plants create their fuel — occurs in the leaves. Therefore, plants need to get fluids and nutrients from the ground up through their stems to their parts that are above ground level.

Explanation: How does a plant get water form the ground.

Answer:

It uses roots that suck up the water.

Explanation:

The roots are like tiny straws located in the bottom of a plant. They suck up water which goes up the stem. And the plants use that water to make food.

The public is not yet able to purchase cars powered by hydrogen fuel cells because engineers have to determine how the cars perform based on which scenario? on racetracks in real-world conditions in flooded environments on closed courses

Answers

Answer:

B - In real world conditions

Makes the most sense.....

Answer:

the answer is b

Explanation:

it's on edge  just did it

UwU hope this helps yall

Cushing syndrome is caused by an increase in the synthesis of cortisol in the adrenal gland. Which of the following compounds is directly required as a substrate for the synthesis of this hormone?
A) cholesterol
B) glucose
C) free fatty acids
D) amino acids

Answers

Answer:

Cholesterol

Explanation:

Cushing Syndrome occurs as a result of exposure of the body to elevated levels of cortisol hormone (stress hormone) for a long time. The elevated level of cortisol which is a steroid hormone, results from increased synthesis of cortisol in the adrenal glands. Cortisol is synthesized from a substrate called, cholesterol. Cortisol synthesis occurs in the zona fasciculata of the adrenal cortex and controlled or regulated by the hypothalamus-pituitary-adrenal axis or HPA axis.

Cholesterol, which is an important substrate in cortisol synthesis, is a lipid usually found in cells and plays an important function in hormone synthesis, food digestion and synthesis of Vitamin D.

Could somebody help me with this please

Answers

Answer: answers are in the explanation

Explanation:

Golgi body

1. To package and transport glycoprotein

2. To secrete synthesised proteins

3. To secrete lysosomes

Endoplasmic reticulum

-Rough endoplasmic reticulum

1. To transport synthesised proteins

-Smooth endoplasmic reticulum

1. To transport lipids

Mitochondrion

1. To increase the surface area for respiration

2. To provide energy for the process of respiration

Ribosomes

1. To serve as site for protein synthesis

what are the different types of experiment​

Answers

EASY

There are three types of experiments you need to know:

Lab Experiment. Lab Experiment. A laboratory experiment is an experiment conducted under highly controlled conditions (not necessarily a laboratory), where accurate measurements are possible. ...

Field Experiment. Field Experiment. ...

Natural Experiment. Natural Experiment.

Study these diagrams. The dots represent valence electrons orbiting the nucleus of an atom. Which diagram shows the valence electron pattern for a carbon atom? Four options A, B, C, and D showing different atomic structures with a nucleus at the center and valence electrons in circular path

Answers

Answer:

The image having four outermost (valence) electrons and a nucleus at the center

Explanation:

Even though the images were not displayed in the question, but we know that carbon is a member of group 14 in the periodic table.

Every member of this group possess four electrons on their outermost or valence shell in addition to the nucleus at the center of the atom.

Hence the structure having four outermost electrons and a nucleus represents carbon atom.

Please help! i'm stuck on this
Grassland ecosystems in Texas have evolved to depend on periodic fires to return nutrients to the soil and encourage plant reproduction. Humans have prevented fires in many of these grassland areas, resulting in plant and animal communities with very little diversity. Wildlife biologists often recommend purposefully starting fires called prescribed burns, which are monitored and controlled, in grassland ecosystems every 3 to 4 years. These biologists observe greater diversity in plant and animal life in the years following a prescribed burn.

What natural process are the biologists attempting to imitate?

Population bottleneck
Succession
Biomagnification
Species extinction

Answers

Answer:

succession

Explanation: this is a hard one but you have to use process of elimination

Click the statement that best describes the role of each element in living organisms.

Answers

what are the statements?

Answer:

Nitrogen : Is obtained by plants from bacteria in the soil

Nitrogen : Is obtained by plants from bacteria in the soil Phosphorus : Provides strength to bones and exoskeletons

Nitrogen : Is obtained by plants from bacteria in the soil Phosphorus : Provides strength to bones and exoskeletons Sulfur : Gives strength to the protein keratin

Hope this help :)

Which type of neuron detects a raindrop falling on skin? cell neuron motor neuron interneurons sensory neuron

Answers

Answer:

Sensory neurons

Explanation:

Sensory neurons carry signals from the external parts of your body to the nervous system.

Motor neurons carry signals from the nervous system to the external parts of your body.

Interneurons connect various neurons within the brain and spinal cord.

Hope this helps! :)

The type of neuron that can detects a raindrop falling on skin is sensory neuron. The correct option is D.

What is a neuron?

The basic building blocks of the brain and nervous system are neurons (also known as neurons or nerve cells).

Neurons are the cells that receive sensory information from the outside environment and are in charge of providing motor instructions to our muscles.

The glial cells and the neurons are the two main subtypes of brain cells. While neurons in the brain play the dominant role, glial cells predominate in certain regions of the brain.

When you contact a hot surface with your fingertips, your sensory neurons will fire and transmit messages to the rest of your nervous system about the information they have just received.

Sensory neurons are the nerve cells that are activated by sensory input from the environment.

Thus, the correct option is D.

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What best describes the role of the squirrel in the food web?

Answers

The squirrel is the prey for larger animals. The consumer 1

Answer:

[tex]\boxed {\tt C. \ A \ primary \ consumer \ that \ is \ food \ for \ a \ single \ predator, \ the \ hawk}[/tex]

Explanation:

First, let's examine the food web and focus on the squirrel. The grass points to the squirrel which points to the hawk. There are no other arrows involving the squirrel.

Therefore, the squirrel is only food for the hawk. We can eliminate A and B.

Now, let's focus on the last two answers.  The difference between C and D is C says "primary consumer" and D says "secondary consumer". Let's define these terms.

Primary consumer

Consumers that eat plants

Secondary consumer

Consumers that eat primary consumers

The arrow points from the grass to the squirrel. The arrow represents energy flow, so the energy flows from the grass to the squirrel (the squirrel eats grass). Grass is a plant, so a squirrel is a primary consumer.

The correct answer is C. A primary consumer that is food for a single predator, the hawk

Explain how natural springs, hot springs, and geysers differ. (Best answer gets brainliest)

Answers

In hot springs the rising superheated water is cooled below the boiling point by groundwater before reaching the surface. In geysers the superheated water collects in underground pockets.

Our current rockets would take tens of thousands of years to get to even the nearest star, 4.3 ly away. If we invent a spacecraft that can travel 0.1 the speed of light, how long would it take to travel to the nearest star?


- 4.3 ye

- 3.8 x 10^14 yr

- 43 ly

- 1.9 x 10^7 yr

Answers

Answer:

It will take the rocket 43 light years to get to the nearest star

Explanation:

1 light year = 9.46 * 10¹⁵ m

speed of light = 3.0 * 10⁸ m/s

In one year, light travels a distance of 1 light year.

A rocket with that travels with a speed 0.1 * the speed of light will travel the distance of one light year in 1/0.1 = 10 light years

Therefore, it will take the rocket 10 * 4.3 light years to get to the star = 43 light years.

43 light years = 43 * 9.46 * 10¹⁴ m = 4.07 * 10¹⁷ m

An organism transforming (caterpillar to butterfly) is an example of which characteristic of life?

Answers

Answer:

metamorphosis

Explanation:

Cell Analogy Writing Assignment

Answers

Answer:

Choose a topic for your cell analogy. Below each topic heading are possible analogies for the topic. You can use them or come up with your own. The fourth column is a space in case you want to make your own analogy topic.

Explanation:

Answer:

Example of a Cell Analogy Story

Explanation:

Cell Analogy Story

A cell can be compared to a business. The Nucleus controls all cellular functions like a Chief Executive Officer that controls all of the operations and decisions of the business. Within the business there is the cytoplasm. The Cytoplasm in a cell, harbors cell organelles and provides structure. This compares to the factory work space that contains all the working bio-machinery and the nutrients, like the raw materials, for the cellular processes. The Cytoskeleton for a cell is what provides the shape and structure to the cell. This is compared to the architecture structure of a factory. It helps to support and strengthen the structure of the building. The Endoplasmic Reticulum of a cell is the site for protein synthesis, the vesicle packaging and transport. This is compared to an assembly line of the business. This is the main work space for production of the important cell components, for example the proteins. The Golgi Apparatus of the cell is the packaging of molecules into the transport vesicles. This is compared to the packaging department of a business. The packing department is the department that packages the goods that have been prepared. The Lysosomes of the cell is actually the membrane-bound cell organelle. It contains the digestive enzymes that break down the excess or the otherwise known worn-out parts of the cell. If the cell is considered damaged beyond repair it will help it to self-destruct with a process that is called programmed cell death. This is compared to the maintenance department of a business. The maintenance department is called in when there is old worn out machinery that needs replaced and discarded. The Mitochondria of the cell is in charge of producing the energy through cellular respiration. This is compared to the power plant or the generator of the business to help the production of energy. There are a few extra parts of the cell that could not be put on the chart above. The Plasma membrane of the cell is the semi permeable that controls cellular transport. This is compared to the Logistics department of the business. This department is in control of what is shipped in and out of the business. The last one is the Ribosomes of the cell. This Ribosomes are like the protein builders or the protein synthesizers of the cell. This is compared to the factory workers of the business. The works build the products for the company.  

Physical properties cannot separate a into the elements it contains

Answers

Answer:

a compound

Explanation:

Answer:

a compound

Explanation:

What is the geographic area where a given population is found? carrying capacity population density distribution range

Answers

Answer:

range

Explanation:

The geographic area where a given population is found is referred to as its distribution range. The geographic or physical boundaries that make up a given population of organisms are represented by the distribution range.

On the other hand, carrying capacity refers to the most members of a species that a particular habitat or ecosystem can support over the long term. It is the maximum population that may exist indefinitely without seriously affecting the environment or exhausting its resources.

A measure of how packed or concentrated a population is in a given area is called population density. The usual unit of measurement is the number of people per unit of habitat or land area. Within a distribution range, population densities can change between areas, indicating how individuals are dispersed within the available environment.

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when is the sun the highest in the sky

Answers

Answer:

around noon

Explanation:

HELP BRAINLY AND FAST!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Which section develops the idea that each species of pine tree is unique? A. Types of Pines B. White Pine C. Identifying Trees D. Pines

Answers

Answer:

A. Types of Pines

How might the DNA-RNA-protein pathway affect cellular differentiation?

Answers

Answer:

For example, cells in the interior of the body may be signaled by genes to become either muscle or connective tissues, while other cells on the exterior of the body will be signaled to become epithelial cells.

Explanation:

Answer: epithelial cells

Explanation:

For example, cells in the interior of the body may be signaled by genes to become either muscle or connective tissues, while other cells on the exterior of the body will be signaled to become epithelial cells.

a scientist is examining the role of an element found in fatd and cabohydrates of living things this element makes up 65% of human body mass which statement describes the element he is studying?​

Answers

The question is incomplete as the group of choices are not provided however the correct group of choices are given as follows:

He is studying oxygen, which can also be found in proteins.

He is studying oxygen, which is the most abundant element in the atmosphere.

He is studying nitrogen, which can also be found in proteins.

He is studying nitrogen, which is the most abundant element in the atmosphere.

Answer:

The correct answer is - He is studying oxygen, which can also be found in proteins.

Explanation:

Human body is comprises of various type of molecules and elements such as fats, protein, carbohydrates and many other elements. Carbohydrates and fatty acids are are made up of 3 major elements carbon, hydrogen and oxygen.

Oxygen is an essential element with 65% of all elements found in human body it shows great affinity with proteins. Oxygen binds with hemoglobin then transferred to the through out the body.  The oxygen is also one of the elements found in proteins with other elements like nitrogen, hydrogen and carbon.

Thus, the correct answer is - He is studying oxygen, which can also be found in proteins.

A sample of food is dehydrated, which kills all of the bacteria. However, in a few days, bacteria-free water is added to the food in a bacteria-free environment. Nevertheless, microscopic investigations indicate that bacteria are in the food. How did the bacteria get there?

Answers

Explanation:

well some bacteria are protected by a special coat outside their body which prevents any water loss from the bacteria. Such bacteria can then reproduce after conditions return to normal.

When a sample of food is dehydrated and making it bacteria-free, but in a few days bacteria are found in the food, it shows, bacteria which are there were in the food as endospores.

What are endospores?

Endospores are the alternate stage of bacteria, which is the dormant stage, genus Bacillus, and the genus Clostridium,  are examples of bacteria that make endospores.

These endospores are resistant to physical and chemical treatments, so this makes it easier for bacteria to survive in stressful conditions. It is a major threat to the food industry which provide heat treatment to the bacteria but they show resistance due to spore formation.

Therefore,  when a sample of food is dehydrated to kill all of the bacteria in the food, but microscopic investigations indicate that bacteria are in the food, it is due to endospores.

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what drives inquiry?

Answers

Answer:

The interpretation including its particular issue is listed in the subsection below on explanations.

Explanation:

The inquiry would be a learner-centered procedure that requires procedures of investigating the natural and perhaps component society and contributes to questions being asked, innovations being made and those discoveries being tested in the quest for alternative comprehension. Because it contributes to scientific literacy, the corporation about doing actual science should be mirrored as accurately as possible.
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