how do scientists calibrate a molecular clock

Answers

Answer 1

Answer: mutations that natural selection can work on. 4.) How do scientists calibrate a molecular clock? ... they compare the number of positive mutations that have occurred in a particular species with the number of negative mutations that have occurred

Explanation:


Related Questions


What kind of genetic disorder is represented in the pedigree?

Answers

Answer:

an autosomal recessive disorder

Explanation:

Autosomal recessive disorders are inherited diseases caused by the presence of two copies (alleles) of an abnormal gene, thereby only homo-zygous recessive individuals are affected by this type of disease. In consequence, although both parents don't express the disease, they can be carriers and pass this recessive disorder to their offspring who express the disease. In this case, the pedigree shows that heterozygous parents are not affected but they are carriers of the recessive allele for this disease, thereby some offspring express the trait. The black circle (female) and the black square (male) indicate affected individuals in the pedigree chart. Since both parents are heterozygous, 1/4 (25%) of all offspring would be expected to have the autosomal recessive disorder.

a group of that works together are called organs

Answers

Answer:

Tissues.

Explanation:

A group of distinct tissues work together & make up an organ which in turn makes an organ system.

Answer: tissues

Explanation: A group of tissues that work together are called organs

NADP+ is converted into NADPH during the light-dependent reactions. Where does the hydrogen
come from?

Answers

It comes from the splitting of water, in the form of hydrogen ions. Oxygen is released as a by-product.

where do organisms live in the ocean

Answers

Answer:

either close to the shore or deeper out into the sea

Explanation:

hope that helps!

Answer: Coastal habitats on the continental shelf, even if this area occupies only 7% of the total ocean area. Most of the open ocean habitats are found in the deep ocean beyond the edge of the continental shelf. Ocean and coastal habitats can be created by species living in them.

Explanation:

Please can anyone help me ill make you the brainiest, I need help with these questions!
1.How many moles of oxygen react with 10.5 moles of methane?
2.How many moles of methane react with 10.7 moles of oxygen?
3.How many moles of carbon dioxide are produced from 80 moles of methane?
4.How many moles of water are produced from 800 moles of methane?
5.How many grams of oxygen will react with 85 grams of methane?

Answers

Answer:

the moles of oxygen react only 1.05 moles

Explanation:

because the formula of methane is CH4 so it has 10 molecule so 10.5 ÷10 =1.05

Which of the following is the best example of diffraction?

Answers

Answer:

you voice echoing back when you shout in a canyon

Explanation:

In general, how might choosing a small sample size affect a scientific investigation?
A. A small sample size is more precise than a large sample size.
B. A small sample size is not as reliable as a large sample size.
C. A small sample size is less expensive than a large sample size.
D. A small sample size has fewer dependent variables than a large sample size.​Following the War of 1812, the United States reached a number of agreements with foreign countries. Match the parts of each

Answers

Answer:

a small sample size is not as reliable as a large sample size

Explanation:

(ASAP please help short writing)
A. Describe the role of the promoter in eukaryotic gene expression. Explain how a negative regulatory molecule could inhibit transcription at the promoter.

B. Identify TWO events that occur during RNA processing. Explain how RNA splicing increases the variation of mRNA molecules.

C. Describe the role of miRNA in gene expression.

Answers

Answer:

Explanation:

A. The role of promoter in eukariotic gene expression is It is to bind transcription factors that regulate transcription initiation. This molecule is so important because control the binding of RNA polymerase to DNA. The promoter region may be short or very long; the longer the promoter is, the more protein binding space is available. A negative regulatory molecule has the possibilty to inhibit transcription at the promoter because these molecules block the binding of RNA polymerase to the promoter region, thus not allowing the initiation of transcription, in some particular cases, the negative regulator binds to the lac repressor and will bind to the promoter in the same site where RNA polymerase would bind to.

B. Two process that occur during RNA processing are RNA splicing and 5′ capping, 3′. RNA splicing is a procces known for removing the introns from the pre-RNA and stuck back together the restant parts, exons. This process has as a goal form a mature mRNA that does not contain the intron sequences. RNA splicing has effect on variation of mRNA molecules because through a process called alternative splicing more than one mRNA can be made from the same gene. 

C. Even though they are not quite the same thing miRNA and negative regulatory molecules have the same role, which is inhibit the translation and silence genes. They regulate gene expression by binding to the 3'-UTR of their target mRNAs and destabilizing the mRNA and translational silencing, repressing protein production. Even so, under specific circumstances, miRNA can activate translation or regulate transcription.

How are carbon dioxide and oxygen exchanged in the lungs?
A. Large blood vessels constrict and enlarge near the the lung tissue so gases can be exchanged.
B. Carbon dioxide and oxygen are exchanged in the aorta.
C. Small blood vessels pass next to the air sacs of the lung, gases are exchanged across a thin membrane.

D. The walls of the arteries thicken, harden, and lose their elasticity so that oxygen can pass through them.

Answers

Lung air sacs are surrounded by small blood veins, and a thin membrane allows for the exchange of gases (option C).

What is the purpose of oxygen?

The chemical process that generates energy and powers the metabolisms of most living things, respiration, depends heavily on oxygen. The oxygen in the air that we breathe is essential for the survival of humans and many other animals.

O2 gas is it just O2?

The sole sort of atom in oxygen makes it a chemical element, which is a substance. An oxidizing agent has eight atoms in its nucleus, as indicated by its atomic number of 8, which is represented by the letter O in its official chemical formula. At room temperature, oxygen is a gas that lacks all other flavors, smells, and colors. Molecular oxygen can be found in nature.

To know more about Oxygen visit:

https://brainly.com/question/13370320

#SPJ1

PLS HELP!! brainliest + extra points! it's easy but i didn't study tbh:)

Answers

Answer:

Guanine to Cytosine

Explanation:

G always matches C

A always matches T

Hope it helps

Plz mark Brainiest.

What is the main idea of this text?

A. Climate change is a complex and unpredictable process involving
feedback loops.
B. Disagreements about climate change have prevented scientists from
finding real solutions to global warming.
C. Wallace Broecker's theory may have been incorrect, but he presented
some worthwhile ideas.
D. Climate change can be completely reversed if carbon dioxide production
is changed.

Answers

Answer:

should be b

Explanation:

Answer:

disagreements about climate change have prevented scientific from finding real solutions to global warming

3. Why does asexual reproduction result in offspring with identical genetic variation? ​

Answers

Because there is only one parent I believe

Answer:

Because the offspring are not getting genetic material from another organism.

Explanation:

What is a change in an organism that allows for it to survive in its
environment?
A.homologous
B.vestigial
C.variation
D.adaptation

Answers

Answer:

d adaptation

Explanation:

its an adaptation because its a change that helps the organism survive

the anthers in this flower located above or below the stigma

Answers

Answer:

The anther produces pollen (male reproductive cells). The filament holds the anther up. During the process of fertilization, pollen lands on the stigma, a tube grows down the style and enters the ovary. Male reproductive cells travel down the tube and join with the ovule, fertilizing it.

Explanation:

Explain why scientists classify organisms and how scientists classify species.

Answers


Scientists use classification to help them decide. Classification is a way to organise living things. They are put in groups with similar features. An example is A finch looks quite different to a peacock, but they both have beaks, wings, and feathers.

The nucleus of a cell is most responsible for what function?

Answers

Answer:

The main function of the cell nucleus is to control gene expression and to mediate DNA replication during the cell cycle. The nucleus provides a site for transcription in the cytoplasm, allowing levels of regulation that are not available in prokaryotes.

The nucleus is like the brain of the cell.

all you need is in the photo

ASAP​

Answers

Answer:

translation; mRNA --> protein.

It includes three steps: initiation, elongation, and termination.

Explanation:

After the mRNA is processed, it carries the instructions to a ribosome in the cytoplasm. Translation occurs at the ribosome, which consists of rRNA and proteins

Francis grew some plants for a science experiment. The sketch of his experiment after several days is shown. Which tropism is Francis most likely investigating?

Answers

The correct answer to this open question is the following.

Unfortunately, you did not provide the sketch or the photo that shows what Francis is doing. So we do not know what you are talking about.  

However, trying to help you, we did some deep research and can comment on the following.

If the photo shows a plan under the light of a lamp, moving towards the lamp direction, then tropism is Francis most likely investigating is phototropism.

To better understand the concept, Tropism is the movement of a plant towards the direction of an influence exerted on it. This means that an external factor is introduced in order to make the plant grow through an external influence.

So when we use the term phototropism, this means that the plant responds to the direction of the source of light and grows in that direction. That is what Francis is using in his science experiment.

Answer:

phototropism

Explanation:

if you want an in depth answer, look at the other one, not mine lol! (I attatched the image)

what is natural selection?​

Answers

Answer: The process whereby organisms better adapted to their environment tend to survive and produce more offspring.

helpppppp plssssssss

Answers

Most likely B is the answer

Groups of ______________
A. Specialized Genes
B. Specialized cells
C. specialized proteins
form____________
A. homeostasis
B. specialized cells
C. organs/tissues
and cooperate to help organisms maintain _________________
A. homeostasis
B. organs/tissues
C. specialized cells​

Answers

Answer:

B

C

A

Explanation:

cells make up tissues and organs ,and matianing homestais is the goal of your body.

Fossil records: Location

Answers

A fossil record is a group of fossils which has been analyzed and arranged chronologically and in taxonomic order.

Hygvhimmcr. Hubcap :)

Neurons and muscle cells perform different functions. In the body, these cells have the same . The function of muscle cells is , while the function of neurons is to send nerve signals.

Answers

Answer: Nerve cells and muscle cells are excitable because their cell membrane can produce electrochemical impulses and conduct them along the membrane.

Explanation:

Answer:

Gentic Makeup, and Movement

Explanation:

What percentage of offspring will have pink flowers

Answers

Answer:

50%

Explanation:

The pink flower donates the r allele and produces pink flowers in 50% of the offspring.

we need a box image to predict how many offspring of pink flowers there will be :/

The infection-fighting cells that are produced by the immune system are manufactured in specific places around the body, for example, in the lymph nodes and the spleen. However, an infection can occur anywhere in the body. How do these infection-fighting cells manage to move around the body and get to the sites of infection?

A. There are lymph nodes every few millimeters all over the body.

B. They are excreted and float freely around the body, hunting infections.

C. They are carried around the body in the circulatory system.

D. They are moved around the body as muscles squeeze against them.

Answers

Answer:b

Explanation:

Answer: C

Explanation:
those cells are white blood cells.

Mr. Shepherd is at a football game on a cold day. How does his body maintain a relatively constant body temperature? What is this process called?

Answers

Answer:

1. Mr. Shepherd maintain a relative constant body temperature by preventing loss of heat.

2 This process is called HOMEOSTASIS

Explanation:

Homeostasis is the process whereby living organisms maintain a stable internal environment despite changes in conditions to the external environment. It is necessary that the body undergoes this process in order to guarantee survival.

According to this question, Mr. Shepherd is at a football game on a cold day. This means that in order to maintain a stable internal temperature, the body must preserve heat in the body and prevent its loss via sweating.

The regulation of body temperature is maintain fundamentally by the thermoregulatory center located in the preoptic region of the hypothalamus, this process is called homeostasis, which is the balance that occurs in the internal environment.

The main thermoregulatory mechanism is the increase or decrease in blood flow to the skin, through vasodilation and vasoconstriction.

Thermal sensing cells or thermal sensors for heat and cold are located on the skin surface (peripheral receptors), in the pre-optic region of the anterior hypothalamus (central receptors) and in other parts of the body.

When it is hot, blood circulation to the skin increases (it becomes red) and when it is cold it decreases (the skin becomes paler).

In addition to blood flow, the body also uses sweat to regulate temperature, sweating evaporates water on the surface of the skin and heat is lost, thereby lowering body temperature.

Therefore, we can conclude that the maintenance of body temperature is closely related to another important indicator, the internal environment (homeostasis).

Learn more about homeostasis here: https://brainly.com/question/965852

In order to create a big storm, the HIGH LEVEL TEMPERATURE had to be... A.Very Cold B.Cold C.Cool

Answers

Question:

In order to create a big storm, the HIGH LEVEL TEMPERATURE had to be... A.Very Cold B.Cold C.Cool

Answer:

A, because in order to create a big storm, the temperature has to be at least  40-20 degrees Fahrenheit (below 30 is freezing point, aka snow), and that would be weather where you would need to wear a thick jacket and warm pants.

If this helped, your welcome! Please know that I might be wrong, and if I am, I am truly sorry for that. But If you would, please make me brainliest.

- niaxfandoms (ig and yt)

can someone help brainliest

Answers

Answer: 1. founder effect

2. evolution

3. natural selection

4. species

5. geographically isolated

Explanation: Good luck! :D

the xx chromosome type is found in__​

Answers

Answer:

[tex]females \: \: \: \: \: \\ it \: is \: your \: right \: answer \: [/tex]

What makes a good rapper?
I will mark you Brainly.

Answers

Answer:

- Rapping on beat

- Bars we understand not just mumbling or repeating the same word over nd over again

- Confidence

Explanation:

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