Answer:
23
Explanation:
Which option(s) correctly describes chromosomes?
Chromosomes consist of tightly coiled DNA wrapped around proteins called histones
Each chromosome has one gene
Chromosome pairs contain completely different genes
Most human cells have two copies of each chromosome - one from each parent.
Answer:In the nucleus of each cell, the DNA molecule is packaged into thread-like structures called chromosomes. Each chromosome is made up of DNA tightly coiled many times around proteins called histones that support its structure.
Chromosomes are not visible in the cell’s nucleus—not even under a microscope—when the cell is not dividing. However, the DNA that makes up chromosomes becomes more tightly packed during cell division and is then visible under a microscope. Most of what researchers know about chromosomes was learned by observing chromosomes during cell division.
Each chromosome has a constriction point called the centromere, which divides the chromosome into two sections, or “arms.” The short arm of the chromosome is labeled the “p arm.” The long arm of the chromosome is labeled the “q arm.” The location of the centromere on each chromosome gives the chromosome its characteristic shape, and can be used to help describe the location of specific genes.
The concept of evolution by way of natural selection is a central tenet in biology that has been tested in numerous ways by many scientists. Evolution by way of natural selection is most likely which type of concept?
A. an explanation of phenomena that can be accepted as true because it is supported by repeated observations and experimentation
B. a likelihood based on the chance that a particular event will or will not occur during an experiment
C. a testable explanation or answer to a scientific question based on prior knowledge or research
D. a statement of fact that is accepted as true because it has always been observed to be true through observations and experimentation
Answer:
I know I am too late to help you, but I couldn't find an answer when looking for this question. I got it right and it is A. an explanation of phenomena that can be accepted as true because it is supported by repeated observations and experimentation.
Explanation:
Evolution by way of natural selection is most likely an explanation of phenomena that can be accepted as true because it is supported by repeated observations and experimentation. The correct option is A.
What is natural selection?Natural selection is the process through which organisms that are more adapted to their environment tend to survive and reproduce more than those that are not. Tree frogs, for example, are occasionally eaten by snakes and birds.
Evolution is a process in which living things or other evolve or change over time. Natural selection is also a reason for evolution, which takes a large amount of time.
Therefore, the correct option is A. an explanation of phenomena that can be accepted as true because it is supported by repeated observations and experimentation
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The ancestors of modern-day fish were vertebrate chordates. Vertebrate chordates are believed to have evolved from invertebrate chordates, which were similar to modern-day tunicates.
What change must have occurred during the evolution from invertebrate chordates to vertebrate chordates?
A.
A backbone evolved to enclose the notochord, which develops from the spinal cord.
B.
An endoskeleton evolved to enclose the spinal cord, which develops from the notochord.
C.
An endoskeleton evolved to enclose the dorsal nerve cord, which develops from the notochord.
D.
A backbone evolved to enclose the spinal cord, which develops from the dorsal nerve cord.
Answer:
The correct answer is option B, that is, an endoskeleton evolved to enclose the dorsal nerve cord, which develops from the notochord.
Explanation:
It has been discovered that the ancestors of the modern-day fish were vertebrate chordates. The vertebrate chordates are considered to have evolved from the invertebrate chordates that are identical to the present day tunicates. It has been found that in vertebrates the endoskeleton has evolved to encompass the dorsal nerve cord that has been developed from the notochord (a characteristic of invertebrates).
Black hair (b) is dominant over brown hair (b) in guinea pigs. What is the genotype of a brown guinea pig?.
Answer:
the genotype of the brown guinea pig would be 'bb'
Explanation:
if it had black hair the possible genotypes would be 'Bb' or 'BB' because any genotype with a capital letter is dominant and brown hair is a recessive trait I'm assuming considering the question says "over"
You touch a hot pan when cooking. List out the steps, in detail, of the nervous pathway of the reflex that occurs. Include any sensory organs involved and the action of the reflex.
Select two options.
What happens during cell respiration?
O The cell takes in oxygen.
O The cell releases oxygen.
O The cell takes in carbon dioxide.
O The cell releases carbon dioxide.
O The cell splits.
Which part of the vascular system functions as a blood reservoir and contains over 60% of the body's blood
Answer:
Veins are also called capacitance vessels because they contain 60% of the body's blood volume.
Explanation:
Hope I could help.
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Which two atoms form an ionic bond?
A.sodium and bromine
B. two sodium atoms
C. two oxygen atoms
D fluorine and chlorine
Answer:
sodium and bromine
Explanation:
The one valence electron from sodium would be transferred to the bromine atom so they can both have an octet.
Which two atoms form an ionic bond?
Answer : A
Explanation : Ionic bond is a type of chemical bond and binds the chemical molecules together. Ionic bond is formed by the transfer of electrons from an electropositive element ( metal) to the electronegative element (non metal).
Sodium is an electropositive element and contains one positive charge. Bromine is an electronegative element with a single negative charge over it. Sodium gives the electron to bromine and results in the formation of ionic bond.
Thus, the correct answer is option (C).
Hope this helps you!
What happens to the peak wavelength in the blackbody spectrum as the temperature of a star increases?
A. The peak wavelength decreases.
B. The peak wavelength increases.
C. The peak wavelength doesn't change.
D. The peak wavelength decreases and then increases
Answer:
D
Explanation: the peak wavelength in the blackbody decreases
Sperm cells have a whip like ____ to move them through a liquid.
Answer:
tail
Explanation:
Answer:
flagellum
Explanation:
a slender threadlike structure, especially a microscopic appendage that enables many protozoa, bacteria, spermatozoa.
Can someone help me with this please? i would really appreciate it
Answer:
I'll try, what is it?
Explanation:
please help asap!!!! will be marked as brainlist !! do not spam or u will be reported
Answer: water cycle: evaporation condensation precipitation
carbon cycle: fossil fuel combustion, co2 in atmosphere, photosenthises prob spelled wrong
Explanation nitrogen cycle bacteria, nitrogen separting bacteria n2, nitrogen in the air, nitrate salts back to bacteria
pro wrong but there ya go
PLEASEEE HELP!! Ill mark brainlist
How/why does the DNA separate?
Discuss porosity or pores, electricity, DNAS charge & size of DNA pieces. Highlight all the 4 terms
Electrophoresis is a technique commonly used in the lab to separate charged molecules, like DNA, according to size.
Gel electrophoresis is a technique commonly used in laboratories to separate charged molecules like DNA?, RNA? and proteins? according to their size.
Charged molecules move through a gel when an electric current is passed across it.
An electric current is applied across the gel so that one end of the gel has a positive charge and the other end has a negative charge.
The movement of charged molecules is called migration. Molecules migrate towards the opposite charge. A molecule with a negative charge will therefore be pulled towards the positive end (opposites attract!).
The gel consists of a permeable matrix, a bit like a sieve, through which molecules can travel when an electric current is passed across it.
Smaller molecules migrate through the gel more quickly and therefore travel further than larger fragments that migrate more slowly and therefore will travel a shorter distance. As a result the molecules are separated by size.
Gel electrophoresis and DNA
Electrophoresis enables you to distinguish DNA fragments of different lengths.
DNA is negatively charged, therefore, when an electric current is applied to the gel, DNA will migrate towards the positively charged electrode.
Shorter strands of DNA move more quickly through the gel than longer strands resulting in the fragments being arranged in order of size.
The use of dyes, fluorescent? tags or radioactive? labels enables the DNA on the gel to be seen after they have been separated. They will appear as bands on the gel.
A DNA marker with fragments of known lengths is usually run through the gel at the same time as the samples.
By comparing the bands of the DNA samples with those from the DNA marker, you can work out the approximate length of the DNA fragments in the samples.
How is gel electrophoresis carried out?
Preparing the gel
Agarose gels? are typically used to visualise fragments of DNA. The concentration of agarose used to make the gel depends on the size of the DNA fragments you are working with.
The higher the agarose concentration, the denser the matrix and vice versa. Smaller fragments of DNA are separated on higher concentrations of agarose whilst larger molecules require a lower concentration of agarose.
To make a gel, agarose powder is mixed with an electrophoresis buffer and heated to a high temperature until all of the agarose powder has melted.
The molten gel is then poured into a gel casting tray and a “comb” is placed at one end to make wells for the sample to be pipetted into.
Once the gel has cooled and solidified (it will now be opaque rather than clear) the comb is removed.
Many people now use pre-made gels.
The gel is then placed into an electrophoresis tank and electrophoresis buffer is poured into the tank until the surface of the gel is covered. The buffer conducts the electric current. The type of buffer used depends on the approximate size of the DNA fragments in the sample.
Preparing the DNA for electrophoresis
A dye is added to the sample of DNA prior to electrophoresis to increase the viscosity of the sample which will prevent it from floating out of the wells and so that the migration of the sample through the gel can be seen.
A DNA marker (also known as a size standard or a DNA ladder) is loaded into the first well of the gel. The fragments in the marker are of a known length so can be used to help approximate the size of the fragments in the samples.
The prepared DNA samples are then pipetted into the remaining wells of the gel.
When this is done the lid is placed on the electrophoresis tank making sure that the orientation of the gel and positive and negative electrodes is correct (we want the DNA to migrate across the gel to the positive end).
Separating the fragments
The electrical current is then turned on so that the negatively charged DNA moves through the gel towards the positive side of the gel.
Shorter lengths of DNA move faster than longer lengths so move further in the time the current is run.
The distance the DNA has migrated in the gel can be judged visually by monitoring the migration of the loading buffer dye.
The electrical current is left on long enough to ensure that the DNA fragments move far enough across the gel to separate them, but not so long that they run off the end of the gel.
Illustration of DNA electrophoresis equipment used to separate DNA fragments by size. A gel sits within a tank of buffer. The DNA samples are placed in wells at one end of the gel and an electrical current passed across the gel. The negatively-charged DNA moves towards the postive electrode. Image credit: Genome Research Limited
tank.
What substances in food provide organisms with energy?
Answer:
A food is something that provides nutrients. Nutrients are substances that provide: energy for activity, growth, and all functions of the body such as breathing, digesting food, and keeping warm; materials for the growth and repair of the body, and for keeping the immune system healthy.
Explanation:
Answer: Carbohydrates
Explanation: Because of the starches and sugars in food, that gives your body‘s main sources of energy.
Which of the following snack foods is comprised mainly of carbohydrates?
Answer:
d. All of the above
Explanation:
help meeeeeeeeeeeeeeeeeeeeeeeee
Answer:
Question is not presented
Explanation:
when they find these similarities they conclude that these organisms have a common
Answer:
Every living creature has DNA
Explanation: hope this helps
4. Use the atomic model below to answer the following questions: 1 pt for each blank
How many protons?
How many neutrons?
What is the name of this atom?
Answer:
for first 1 its 3 nuetros i think
organisms composed of one or more cells are known as
Answer:
multicellular organisms
Explanation:
Multi means many or more than one and so multicellular literally means many cells.
Hope this helps!
the largest and most numerous of the glial cells in the central nervous system are the
Answer:
The largest and most numerous of the glial cells in the central nervous system are the astrocytes
Explanation:
hope this helps!
A student is researching the inheritance patterns of different traits in chickens. She hypothesizes that red feathers are dominant over black, and the trait for crests are dominant over non-crested. She performs a test cross to confirm her hypothesis. To produce the F1 generation, she crosses two parents-- a chicken that is homologous for traits showing red and crested and a chicken that is homologous for traits showing black and non-crested. Which ratio best represents the phenotype of the F2 generation
9:3:3:1
1:1:1:1
2:2:1:1
16:0
Answer:
9:3:3:1
Explanation:
In this inheritance pattern, the ratio that best represents the phenotype of the F2 generation is 9:3:3:1. Thus, the correct option for this question is A.
What is a Phenotype?A phenotype may be defined as the mechanism of expressing genotypes in the form of traits. In more simple words, it is also characterized as the morphology or physiology which comes due to the combination of alleles.
If a trait of red feathers is denoted by R and the trait of black feathers is denoted by r, then R > r. Similarly, a trait of crests is denoted by C and the trait of non-crested is denoted by c, then, C > c.
Now, RRCC is crossed with rrcc, the F1 offspring have the genotype RrCc with the phenotype of red feathers with crests. Now, RrCc is selfed, it produces the ratio of 9:3:3:1. This is an example of a dihybrid cross.
Therefore, in this inheritance pattern, the ratio that best represents the phenotype of the F2 generation is 9:3:3:1. Thus, the correct option for this question is A.
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what is a spygnomanometer ?
Answer:
an instrument for measuring blood pressure
Explanation:
an instrument for measuring blood pressure typically consisting of an inflatable rubber cuff which is applied to the arm and connected to a column of mercury next to a graduated scale, enabling the determination of systolic and diastolic blood pressure by increasing and gradually releasing the pressure in the cuff.
There are two types of reproduction, sexual and asexual Sexual reproduction involves two parents, while asexual reproduction only involves one,
Sort the reproductive processes below according to whether they are asexual or sexual.
ITEM BANK: Move to Bottom
Creation of an egg
Creation of fruit
Mushrooms producing spores
Production of seeds
Stem cuttings of plants
Sexual
Asexual
Budding in yeast
drag and drop answer here
drag and drop answer here
Answer:
Creation of egg- Sexual
Creation of fruit - Sexual
Mushrooms producing sporea - Asexual
Production of seed - Sexual
Stem cutting - Asexual
Budding in yeast - Asexual
Which nerve is responsible for hiccups?
Answer:
b. Phrenic nerve
Explanation: is correct
state the expressed power you think is the most important and explain why you think it is the most important.
Answer:
The most important powers include the power to tax, to borrow money, to regulate commerce and currency, to declare war, and to raise armies and maintain the navy. These powers give Congress the authority to set policy on the most basic matters of war and peace.
Explanation: If I am wrong then i am sorry
Which of the following nerves is responsible for hearing and balance?
Answer:
b. Vestibulocochlear nerve
Explanation: is correct
Biology cell division
What are the answers to this chart
The cell spends most of the time in the interphase, which is in the G1, S, and G2 phases, and approximately 22 hours out of 24 hours, with the rest being 1–2 hours, are spent in the division phase.
What is the time spent in the cell cycle?
The cell enters the cell cycle, and the first stage is the G1 phase, where the cell grows and spends a lot of time nearly 11 hours and then the cell enters the S phase. In the S phase, the DNA replicates and spends nearly 7 hours, and then in the G2 phase, 3 to 4 hours are spent by the cell, with the remaining 1 to 2 hours spent in the M phase, also called the mitosis or division phase.
Hence, cells spend most of the time in the interphase, which is in the G1, S, and G2 phases, and approximately 22 hours out of 24 hours, with the rest being 1–2 hours, are spent in the division phase.
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The farm business has decreased for years
due to an increase in disease and pests.
What is one way to increase the production of
crop for the farmers?
A.Plant genetically modified crops.
B.Use water treated with disease control substances to
water the crops.
C.Fertilize the farming land.
D.Increase the use of pesticides to prevent pest.
Which of the following best explains what will happen if the blood gets too cold? A) It will have a high viscosity and increased resistance. B) It will have a low viscosity and increased resistance. C) It will cause low blood pH and decrease resistance. D) It will change the shape of blood cells and decrease resistance.
It will have a high viscosity and increased resistance.
Effect of temperature on bloodLow temperatures cause narrowing of blood vessels and arteries which leads to restricting blood flow and reducing oxygen to the heart.
Our heart must pump harder to circulate blood through the blood vessels which results in increasing of our blood pressure and heart rate.
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Answer:
The correct answer is A
Explanation:
i got it correct on my flvs exam
birds and mammals are both endothermic. i.e. they maintain body temperature internally through metabolism rather than from the environment. how would you explain this, given the position of the two groups of animals on the phylogenetic tree?
On the phylogenetic tree, (a diagram used to show relatedness among organisms) the birds and mammals are closely related to each other and they both are characterized as endothermic.
Given the position of the two group of animals on the phylogenetic tree, their similarity with regards to maintaining body temperature is due to the fact that their evolution involves a more recent ancestor compared with the other vertebrates.
As organisms evolve beginning from invertebrates through to vertebrates, the body system becomes more complex and as they evolve within the vertebrate group.
Some vertebrates like reptiles and amphibians that were dependent on the environment to regulate their temperature while others like birds and mammals forms complex system that enable them live on land and regulate their temperature independent of the environment.
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