Why are the best index fossils from species that only existed for a short period of time ?

Answers

Answer 1

Answer:

Because once they were very common they disappeared after the mass extinction event. ... Many geologic periods were defined by events that made natural boundary to the period.

Answer 2

Answer: Because once they were very common they disappeared after the mass extinction event.

Explanation: Hope this helppssss!!! :)


Related Questions

summarize the future use of dna technology here in 20 words or more

Answers

The Future of DNA Profiles: From Personalized Medicine to Facial Composites. In just a few years, DNA fingerprinting, which analyses small variable genomic regions, would become a common tool used throughout the world, both for law enforcement purposes and for paternity tests.

Answer:

DNA testing has gone mainstream. The cost of DNA sequencing has reduced faster than Moore's Law. With an estimated cost of $100 in the foreseeable future, DNA sequencing becomes more accessible and opens up new use cases, such as wider adoption of population sequencing

Explanation:

Pls can someone help me out by answering these

Answers

Answer:

the diagram is not clear enough.

Answer:

A,C,D

Explanation:

Weak hydrogen bonds between the nitrogenous base pairs hold the two strands of DNA together. Why are the strands held together by weak hydrogen bonds instead of covalent bonds

Answers

Answer:

Explanation:

Hydrogen bonding is usually occur wen interaction with hydrogen atoms occur.

Hydrogen bonds joins DNA polymers because an hydrogen atom occur on on one base which is called hydrogen bond donors and another oxygen or nitrogen atoms on the base across from it which is called hydrogen bond acceptors.

Adenine “A” a purine and Thymine “T” a pyrimidine each have a donor and one acceptor, whereas Cytosine “C” a pyrimidine has one donor and two acceptors, and Guanine “G” a purine has one acceptor and two donors.

This atoms allows for hydrogen bond between them that gives them structure of DNA molecule.

A nucleotides is hydrogen bonded to T nucleotides while C nucleotides is hydrogen bonded to G nucleotide this is called complementary base pairing.

3. Which of the following is an organelle?
(2 Points)
Mitochodria
DNA
Phospholipid
Nucleus

Answers

Answer:

mitochondria and nucleus

I also agree I think it’s Nucleus and Mitochondria

Why does the body produce more urine on a cold day rather than a hot day if the same amount of
water is consumed?

Answers

Explanation:

During summer when the surrounding temperature is high, we lose water in the form of sweat, direct evaporation considerably. Hence kidneys retain water for maintaining fluidity of the blood and less urine is formed.

But during winter, the surrounding temperature will be very low. There will not be any sweating, no evaporation losses. Moreover to keep the body temperature constant, the blood capillaries in the skin get constricted and the blood pressure is increased. The result is that our body gets warmed up. In order to maintain the blood pressure normal, the excess water along with the wastes is excreted mostly in the form of urine. This is the reason for more urine out put and frequent urination under very cool conditions and in winter.

Which characteristics do birds and mammals share? Check all that apply.

Both give birth to live young.
Both are endotherms.
Both have hair or fur.
Both produce milk to feed their young.
Both are vertebrates.

Answers

Answer:

B). Both are endotherms

Explanation:

Both birds and mammals are warm-blooded, which is the meaning of endotherm.

Hope this helps!

~PurpleMist

Answer: B

Explanation: brainlest

The mass of a proton is the same as the mass of a neutron

True or false

Answers

Answer:

This statement is true.

Explanation:

Both protons and neutrons have a mass of one.

Hope this helps :)

Answer:

The proton and neutron have similar mass with the mass of the neutron slightly larger than that of the proton. Each of these particles has a mass approximately 1800 times greater than that of an electron. ... The atomic number of an element is equal to the number of protons in the nucleus of an atom of that element

The __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ carries low oxygen blood to the lungs and brings high oxygen blood back to the heart.

Answers

Answer:

Pulmonary blood vessel

Explanation:

The pulmonary blood vessel carries low oxygen blood to the lungs and brings high oxygen blood back to the heart.

More specifically, the pulmonary artery carries low-oxygen blood to the lung from the right ventricle of the heart. The blood becomes oxygenated in the lung and the oxygen-rich blood is taken back to the left atrium of the heart by the pulmonary vein.

You are comparing the density of sea water to the density of fresh water. (Remember,
density is mass divided by volume.) Describe how you could determine the density of
sea water, including the names of the equipment needed to make the required
measurements.

Answers

Answer:

To know and compare the difference between the density of the fresh water and salt water or sea water require a graduated cylinder, balance, and weighing machine. The graduated cylinders are the containers that have markings on them to measure the volume of the liquid.

First, fill the cylinder with 1000 ml of fresh water which is the measure of the volume. now weight the cylinder filled with the fresh water and then find the difference between filled and empty container divide the mass of the fresh water by its volume, the result is the density of fresh water.

Repeat the process with salt water or sea water. The answer would be sea water has more density than fresh water.

I need help ................​

Answers

Answer:

thats easy bro ;0

Explanation:

A student is presented with a model of a digestive system and is asked to remove one structure (small or large organ) that will have the largest impact on decreasing chemical digestion. Which structure should the student remove

Answers

Answer:

Small intestine

Explanation:

Digestion is the process of breaking down food molecules into simpler and usable forms by the body cells. The process of digestion involved the mechanical aspect and chemical aspect. The mechanical one deals with using physical means like chewing to break down the food particles.

However, the chemical one deals with the usage of chemically-secreted enzymes to work on the food molecules. Lots of digestive organs are involved in this chemical digestion, but, the most of chemical digestion takes place in the SMALL INTESTINE. The small intestine is where most of the chemical digestion occurs including absorption.

Hence, according to this question, the student should remove the SMALL INTESTINE because it will have the largest impact on decreasing chemical digestion.

As mountains are worn down, the eroded metamorphism is deposited
on adjacent landscapes
A: True
B: False

Answers

Answer:

I believe it is true

Explanation:

but im not 100% sure

In a plant species, the allele for dark green leaves (D) is dominant over the allele for light green leaves (d). A plant with Genotype (Dd) is crossed with a plant with genotype (did). What percentage of the offspring are expected to be hybrid for the leaf color trait. A 0% B 25%. C.50%. D 75%

Answers

Dd is crossed over with dd.
So, as we set the punnet square. We get (2)Dd and (2)dd. So 100/2 = 50%.
Correct choice - C 50%.

The percentage of the offspring that is expected to be hybrid for the leaf color trait is 50%. The correct option is C.

What are alleles?

The trait is caused by a pair of two alleles on the chromosome, and there are two possible outcomes. The dominant allele, which is typically written in capital letters and will control the organism's phenotype even in the presence of the other allele, is the one that has the ability to silence the other allele.

It is used in biology to refer to inherited traits that do not manifest in the phenotype of the individual who possesses them but may do so in their offspring.

Recessive alleles, which are only expressed when they are homozygous, are this other type of allele. Both heterozygous and homozygous genotypes exhibit the dominant allele.

Dd is crossed by dd.

100 / 2 = 50%.

Therefore, the correct option is C.

To learn more about alleles, refer to the link:

https://brainly.com/question/7602134

#SPJ6

what if living cells released all their energy at once​

Answers

Answer:

they will lose their energy and die

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(Giving brainliest!!)

Explain why the sun appears to be the brightest star in the sky. Relate your explanation with an example, such as streetlights

Answers

Answer:

when you look a streetlight from far it will be some how not bright. the other stars are far from planet earth . but the  sun is near

Explanation:

what is the effect of glucagon?​

Answers

The effect of glucagon can get you nausea, vomiting, headaces, rhinorrhea and nasal pain.

Use the following questions to write your conclusion to your lab report.

What did you learn from doing this lab? (Did the volcano have an effect on the ability of a predator to catch their prey? What might this mean for future generations? Include numbers from your data tables to show these changes.)



How could you make the lab better?

Answers

Answer:

WHat??

Explanation:

In order to extract DNA from strawberry cells, what will need to happen at the cellular level?

Answers

Answer:

Tiene que romperse la membrana plasmática para poder acceder al núcleo de la célula y posteriormente romperse también la membrana nuclear para dejar libre al ADN

Explanation:

a population of 100 insects that live in an area 100 square meters has a density of 1 insect per square meter. what’s this an example of?

Answers

population density...?

Draw a picture or write a sentence using these words to show how they are related.
DNA, Trait, Alleles, Protein, Genes

Answers

Answer:

DNA

Explanation:

PLEASE GIVE ME A HEART

NS
What are magnetic field lines?
A. Lines that show the shape of a
magnetic field
B. Lines that show the path of electrons
C. Lines that show aligned atoms

Answers

Answer:

A

Explanation:

Magnetic field lines are a visual tool used to represent magnetic fields. They describe the direction of the magnetic force on a north monopole at any given position. The density of the lines indicates the magnitude of the field.

Im not sure if anyone knows this or not.
Can someone please help me with 1 and 2! If u r correct ill mark u was the best answer

Answers

I'm pretty sure the answer to 1 is A, but I know for a fact that soil contains microorganisms and microbes.

The answer to question 2 is D (Porosity)

What are some benefits to evolutionary adaptations?

Answers

Answer:

1.A new species

2.Adding to world population

3.More to learn

Explanation:

Some genes are important enough to be called "molecular switch" or "master" genes. What is the purpose of these genes?

A. They control when other genes are expressed
B. They determine the organization of the genome
C. They regulate cell metabolism
D. They modulate the rate of translation

Answers

Answer:

Genes called "molecular switch" or master genes have the purpose of control when other genes are expressed (option A).

Explanation:

Master gene is so named because it has the function of controlling the behavior of other genes, organizing their functions and regulating when they can be expressed.

The name of molecular switch is synonymous with the master gene, since its activation determines the genetic regulation necessary to establish cell differentiation and even the determination of the sex of some species.

The other options are not correct because:

    B. Master genes do not determine the organization of the genome .

    C. Regulation of cell metabolism depends of substances as hormones and enzymes.

    D. The rate of translation does not depend on the activity of master genes.

In silkworms,yellow cocoon (B) is dominat over white cocoon(b). If the mom is BB and the dad is bb, what are the chances they have offspring with yellow cocoons?

Answers

Answer:

100 %

Explanation:

Dominance is a genetic phenomenon where a gene variant or allele masks the effects of another allele (of the same gene) in heterozygous individuals. This last gene variant is referred to as the recessive allele. In this case, the silkworm mother can produce only one type of gamete carrying the dominant gene (B) form, while the silkworm father can produce only one type of gamete carrying the recessive gene (b) form. In consequence, from this cross, all offspring (100 %) will be heterozygous (Bb) and therefore they will express the dominant trait (i.e., yellow cocoon).

In the laboratory, yeast cells are usually grown at a temperature of 25oC. A scientist wanted to determine if yeast cells would reproduce faster or slower when the temperature was dropped to 15oC. The same number of yeast cells were placed in the same medium with the same amount of nutrients. One sample was kept at 25oC and the other one was kept at 15oC. The number of yeast cells was counted every hour for an eighteen hour period.

Answers

Answer:

This question is incomplete, however, it is asking to identify the following variables:

Independent variable: Temperature

Dependent variable: Number of yeast cells

Constants: same amount of nutrients, same number of yeast cells, same medium

Explanation:

- Independent variable is the variable that the experimenter changes or manipulates in order to bring about a measurable effect. In this experiment, the TEMPERATURE at which the yeast are kept is the independent variable.

- Dependent variable is the variable that responds to the changes made to the independent variable. It is the variable that is measured by the experimenter in the experiment. In this case, The NUMBER OF YEAST CELLS was counted, hence, it is the dependent variable.

- Constants are variables that are kept unchanged or same for all groups by the experimenter in order not to influence the experiment's outcome. In this case, the CONSTANTS are: same amount of nutrients, same number of yeast cells, same medium etc.

. The small fish are not affected by the pesticide, but death occurs in the bird, at the top of the food chain. Why do you think that happens?

Answers


Small fish absorb minute amounts of pesticides.

The birds of prey consume many fish to satisfy their dietary needs. The pesticides accumulate and concentrate in the bird, continued exposure overwhelm the predator.

What is a Metamorphic Rock?

rock that forms when existing rock changes to a new rock because of heat and pressure


rock that forms by the process of compaction and cementation of sediments


rock that forms when melted rock (magma, lava) cools and hardens


pls help

Answers

Answer: A) rock that forms when existing rock changes to a new rock because of heat and pressure ..hope this helped!

Explanation:

What needs to happen for a species to form

Answers

Answer:

New species form when individuals from diverging populations no longer recognize one another as potential mates, or opportunities for mating become limited by differences in habitat use or reproductive schedules.

Explanation:

Need help plz!!! Trying to catch up on biology anything can help!!!!

Answers

Answer:

See the answer below

Explanation:

The control group in an experimental study is the subject group that is not administered the treatment variable. The control group forms the baseline for comparing the effects produced by the treatment variable on the experimental group.

Thus, in this case, the control group would be the 10 mice that were not exposed to the radio waves.

The independent or the manipulated variable, in this case, is the exposure or otherwise of the mice to the radio waves.

The dependent variable is the actual variable that is going to be measured, otherwise known as the effect variable. In this case, the dependent variable would be the strength of the mice measured by their ability to push the block of wood blocking their food.

Since 8 out 10 mice and 7 out of 10 mice were able to push the wooden block in both the experimental and the control group, Bart's conclusion should reject the hypothesis that the radio waves make mice extra strong.

Bart's experiment can be improved by increasing the number of subject mice in each group. The more the number of subjects, the more the accuracy of the outcome would be.

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Pls help due ASAP Show workings pls Danielle lives in a country that calls the Prime Minister the chancellor. What country does she live in? pollution in the____will have the greatest effect on human health. What fraction is greater than -2/3 and less than -1/2 I need help!!! I will give YOU brainliest if you answer something I like!What is good about using a personal tone in an article 25 POINTS!!! The equation y=470x represents the relationship between x, the time that a plane flies in hours, and y, the distance the plane flies in miles for plane A. The table represents the relationship for plane B. Find the slope of the graph for each plane and the plane's rate of speed. Determine which plane is flying at a faster rate of speed. Look at the photo. Which statement best evaluates the effectiveness of this conclusion paragraph?Thesis: Stores across the country should switch from using plastic bags to using paper bags. Main points: 1. The energy cost of making plastic bags 2. How plastic bags contribute to litter3. The benefits of paper bagsConclusion: To summarize, plastic bags have a high energy cost and contribute to the nation's litter problem. Furthermore, paper bags have many more benefits than plastic bags. Stores, and not just customers, should make the right choice: paper, not plastic.A. This conclusion is effective because it restates the thesis statement in a new way.B. This conclusion is ineffective because it does not summarize the main points of the essay.C. This conclusion is ineffective because it fails to provide a satisfying close.D. This conclusion is effective because it adds new information not addressed in the main points. What is the role that genes play in making proteins?I need answers like asap plz help What is the biome located to the south of the tundra Called? Lala eats three times as many pancakes as her little sister Carmen. If Carmen eats m pancakes, how many pancakes does Lala eat? 6. The two kinds of cells are Prokaryotes and Eukaryotes. How are theydifferent? *Prokaryotes have a nucleus.Prokaryotes are plant cells.Eukaryotes have a nucleus.There is no difference. Andie has a goal to complete 70% of the jumps on a skateboard course. If she has completed 30 jumps out of 50total jumps, how many more jumps does Andie need to complete to reach her goal? Martin is helping his mom set up for a school event. His mom put 150 cups into a box. There are 40 red cups, 60 blue cups, and50 green cups in the box. He randomly picks 90 cups from the box and sets them out on tables.How many blue cups is he likely to have set out on tables? Caroline works 18 hours a week at a restaurant and earns $8.25 per hour. She also earns tips, which are 15% of her food sales. In one week, she earned $263.25. Write an equation to find x, her total food sales for that week. A company buys up its competitors and forms one giant company. This is an example of consolidation? Vertical or horizontal which of the following was an argument made against slavery in the 13 colonies I need help on this assignment Item 17 Which symbol represents a salt? C2H2 C6H12O6 KCl O2 Item 17 Which symbol represents a salt? C2H2 C6H12O6 KCl O2 please help it's due today Jason works for a restaurant that serves only organic, local produce. Whattrend is this business following?digital marketing green business e commercediversity