why do you think scientists use mass extinctions to separate one era from another

Answers

Answer 1

Answer:

Eons, Eras and Periods are the three basic units of classification.

Explanation:

Geological time is broken down into Eons (very long term units), Eras (medium term) and Periods (shorter) units. There is also a fourth unit called Epocs that are even shorter time periods, but used mostly by specialists.

The boundaries between various units was initially determined by breaks in the fossil record. For example, the end of the Palaeozoic was when trilobites died out. End of the Mesozoic when the dinosaurs died out and so on.

With the discovery of radiometric dating, these boundaries could be determined more precisely and finer subdivisions, like Epocs, were possible.

More recently, from about 1970 onwards, there was growing evidence that many/most of these boundaries coincided with mass extinction events that killed off huge amounts of species.

Geologist are thinking of adding a new Epoc called the "Anthropocene" to reflect a time when us humans have had such a profound impact on the planet (mostly for the bad!). But to do this, would require a clear boundary in the geological record so that future geologist could recognize it - one option under consideration would be the radioactive fallout layer that occurs around the world from above ground atomic bomb testing in the 50's and 60's. This layer will be around for 10's of thousands of years or longer.


Related Questions

This river is found in western Africa and runs from Guinea to Nigeria.

Answers

Answer:

Niger it sounds bad. but i do believe this is it.

the impact that the increasing number of social grants may have on the Unemployment rate​

Answers

Answer:

This means that social grants increases the "reservation wage" of low-income families, thus they become less motivated to earn. This results to a higher unemployment rate.

Explanation:

Increasing the number of social grants can help reduce unemployment rate.

Unemployment

Unemployment is a situation in which it is difficult for someone searching for a job to get work.

Increasing the number of social grants can help reduce unemployment rate. These grants can serve as capitals for the unemployed to start up their business.

Find out more on Unemployment at: https://brainly.com/question/305041

Hi guys im new please help me

Answers

Returning to Cuba, Castro took a key role in the Cuban Revolution by leading the Movement in a guerrilla war against Batista's forces from the Sierra Maestra. After Batista's overthrow in 1959, Castro assumed military and political power as Cuba's Prime Minister.

Which of the following choices is an example of an extrinsic reward?

-peace of mind

-a sense of accomplishment

-money for good grades

-happiness

Answers

Answer:

money for good grades

Explanation:

cause people do it for a reward

Extrinsic rewards include things like cash for good grades. As a result, Option (C) is the best option.

What is an extrinsic reward?

An employee receives an extrinsic incentive, which typically has a monetary value, for accomplishing something. Pay increases, bonuses, and benefits are examples of extrinsic rewards. Because they are independent of carrying out the actual task and are managed by anyone other than the employee, they are extrinsic.

Extrinsic motivation involves acting in a way that you hope will result in a reward or save you from receiving a penalty, whereas intrinsic motivation involves acting in a way that you hope will result in a personal reward for you.

Extrinsic motivation is significant because it can be a useful tool for changing behavior. The possibility of getting rewards or penalties from outside sources frequently motivates people to act in specific desirable ways.

Hence, Option (C) is the accurate one.

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____ compiled standards for accreditation for the Office of a Medical Examiner.


The National Association of Medical Examiners

The Checklist of Accreditation

The National Association of Medical Doctors

The National Association of Autopsy Standards

Answers

Answer:

The National Association of Medical Examiners

Explanation:

The National Association of Medical Examiners compiled standards for accreditation for the Office of a Medical Examiner.

The actual number of births occurring to women of childbearing age.
a. Population
b. Demography
c. Birthrate
d. Fertility
e. Fecundity
f. Mortality

Answers

Answer:

d. Fertility

Explanation:

The actual number of births occurring to women of childbearing age is fertility. The correct option is d.

What is fertility?

Fertility can be understood as the capability to produce offspring through reproduction following the onset of sexual maturity. The fertility rate is the average number of children born by a female during her lifetime and is quantified demographically. Fertility is addressed when there is a difficulty or an inability to reproduce naturally, which is referred to as infertility.

Infertility is widespread, with fertility specialists available all over the world to assist mothers and couples who experience difficulties having a baby. Human fertility depends on factors of nutrition, sexual behaviour, consanguinity, culture, instinct, endocrinology, timing, economics, personality, way of life, and emotions. Fertility differs from fecundity, which is defined as the potential for reproduction.

Where a woman or the lack of fertility is infertility while a lack of fecundity would be called sterility.

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Who was the leader of the Mexican revolution?

Simon Bolivar

Jose de San Martin

Father Miguel Hidalgo

Toussaint L'Ouverture

Answers

C. Father Miguel Hidalgo also called the father of Mexican independence.

What caused tensions between the US and the Soviet Union fallowing WW2

Answers

Answer:

The Cold War

Explanation:

The Cold War (not exactly a war) was what was caused after the World War 2 conflict. The Souviets wanted to establish a communist regime, while the United States and it's allies preferred a democratic government. The Souviets had won the war and got a lot of countries that Germany invaded (Hungary, Poland, etc.) Nuclear tensions and arms tensions began to complicate the globe.

how did the great drepression contribute to the situation show in the photograph?

Answers

Answer:

Read the below

Explanation:

So I have no idea what you mean by this question so ima give it my best shot, The great depression made stocks fail and many companies were losing there empoloies and nobody was really hiring ( sorry for the bad spelling )

True or False

1. The Tropical North is composed entirely of independent nations.



2. Niagara Falls is more than 20 times higher than Angel Falls.



3. The Tropical North has coastlines on both the Atlantic and Pacific Oceans.



4. Some Tropical North countries have been ruled by dictators.



5. Colombia’s Pacific coast region is heavily populated

Answers

True
No explanation needed

what is the function of redblood cells

Answers

Answer:

Explanation:

Red cells contain a special protein called hemoglobin, which helps carry oxygen from the lungs to the rest of the body and then returns carbon dioxide from the body to the lungs so it can be exhaled.

Hope this helped!!!!

Calling all feminists: why are you feminist?

Answers

Answer:

because someone needs to speak up for woman rights as u may recall lowell system when woman "revolted" and wanted to be equal and have equal pay if men wont stick up for female we have to stick up for our self not only that but how woman get treated as a toy and yes someone like taht but most people dont like getting toched were hands shouldnt

be plus woman get less pay then men

PLS HALP... Your principal wants to invite a celebrity speaker to your school. Think about the celebrity you would choose to have speak; then, write a letter to persuade your principal to invite this person. Be sure to include convincing reasons and details to support your choice. Don’t forget to discuss why this person would be an educational lesson and an inspiration. What does this person do that makes them a role model?
PLS

Answers

Answer:

I would choose michelle obama.

Explanation:

Hi Ms.Obama, My school is having a celebrity speaker and I really would love it if you came.  I KNOW you are the right choice to come to my school because you are a inspiration to me. to be the first black female to be the first lady. you are smart, loving and caring of all colors, shapes and sizes. so I would really love if you could come to speak at my school.

Sincerely,

   Name...

which of the following lamnguges is the most widely spoken in central Asia?

Answers

Answer:

Russian is the number 1 language spoken in central Asia.

Explanation:

Which of the following examples meets the definition of exploitation?

-Allowing a child to compete in a very challenging sports competition.

-Forcing a child to model inappropriate clothing against her wishes and interests.

-Failing to feed a hungry child in your care.

-Yelling at a child every time she drops something.

Answers

Forcing a child to model inappropriate clothing against her wishes and interests


How is racism socially constructed in our culture ?

Answers

Answer:

racism is  a social constuct, its like saying people with blonde hair and under people with brown hair. its made by society

Explanation:

Define self awareness and factors that you may consider to develop your self awareness ​

Answers

Answer:

Definition: Conscious knowledge of one's own character, feelings, motives, and desires.

Factors: Being yourself

Explanation:

Who would be invited or inclined to attend a hearing on a bill

Answers

Answer:

people who would be affected by the bill

Explanation:

This map shows the Middle East around 1600. Which region was ruled by the
Safavid emperor?
Europe
Asia
Black Sea
Istanbula
Caspian
Α.
C
Persia
Mediterranean Sea
India
D
Gulf
Persian

Answers

Answer:

Safavid dynasty, (1501–1736), ruling dynasty of Iran whose establishment of Twelver Shiʿism as the state religion of Iran was a major factor in the emergence of a unified national consciousness among the various ethnic and linguistic elements of the country.

Systems of canals and pumps like the ones shown in this photograph
above help the Netherlands create more dry land. What is this an example
of?
A. how humans in different countries create economic patterns
B. how humans use technology to make places more suitable for humans
C. how humans make international trade easier by creating canals
D. how humans adapt to their environment

Answers

B how human use technology to make place more suitable

Can somebody please help me!!

Answers

Answer:

1. Oil had many functional uses such as cooking, heating, and lighting. For example, oil lamps used oil and were a great source of lighting during that time.

2. Crude is another word for unprocessed, or unfiltered oil (oil that is not ready for use).

3. Refineries were used to process or "filter" the oil to make it useful without emitting more dangerous gases to people using oil.

Which is not a feature of urban life​

Answers

Question

Which is not a feature of urban life​?

Impersonal relationship

PLZ BRAINLIEST + THANKS :)

Answer:

Urban life contains a lot of competition amongst the people living such a life people are literally in a rat race and they hardly have the time to build personal and deep bonds or relationships.

In the following excerpt from Antigone, by the classical Greek playwright Sophocles, the wise Teiresias observes
"Think: all men make mistakes, But a good man yields when he Knows his course is wrong, And repairs the evil: The only Crime is pride".
Think about the implications of the quotation. Write an essay that argues your position on the validity of the assertion from the Antigone excerpt.

Answers

Answer:

Explanation:

In
the
following
excerpt
from
Antigone,
by
classical
Greek  

playwright
Sophocles,
the
wise
Teiresias
observes,  

“All
men
make
mistakes,
but
a
good
man
yields
when
he  

knows
his
course
is
wrong,
and
repairs
the
evil;
the
only
crime  

is
pride.

Take
some
time
to
think
about
the
implications
of
the  

quotation.  Then
write
a
carefully
reasoned
essay
that
explores  

the
validity
of
the
assertion
that
uses
examples
from
a
variety  

of
readings,
observations,
or
experiences
that
develop
your  

position

3. How did the U.S. economy change when the United States entered World War II?
A- Many women lost their jobs.
B- African American workers faced discrimination.
C- Factories shifted to producing materials needed to fight the war.
D- The military began drafting factory workers.

Answers

Answer:

Factories shifted to producing war materials

Factory Shifted to producing materials needed to fight the war instead of what they usually would’ve made

Name and explain two laws/legislation that protect citizens against human trafficking

Answers

Explanation:

rafficking Victims Protection Reauthorization Act of 2003. Trafficking Victims Protection Reauthorization Act of 2005. Trafficking Victims Protection Reauthorization Act of 2008. Trafficking Victims Protection Reauthorization Act of 2013 (Title XII of the Violence Against Women Reauthorization Act of 2013)

The two laws that protect citizens against human trafficking are Trafficking Victims Protection Reauthorization Act, 2003. Trafficking Victims Protection Reauthorization Act, 2005.

What is human trafficking?

Human trafficking is the commerce of humanities for the intention of involuntary labor, physical slavery, or mercantile physical exploitation for the vender or another.

The descent of organs or body part, including for surrogacy and egg cell removal.

To avoid and punishes the human trafficking, parliament makes many laws like, trafficking Victims Protection Reauthorization Act of 2003 and  Trafficking Victims Protection Reauthorization Act of 2005.

The above two laws acted against a person who are engaged in human trafficking and support the human trafficking, and it gives protection to all from the human trafficking.

Therefore, the two laws that are against the human trafficking are trafficking Victims Protection Reauthorization Act of 2003 and  Trafficking Victims Protection Reauthorization Act of 2005.

Learn more about the human trafficking, refer to:

https://brainly.com/question/1163922

B. Which source contains a critique of communism and/or the Soviet Union?​

Answers

Answer:

Eventually, they concluded that the Soviet Union sought to eliminate freedom ... each argument contains a word that is key to identifying its corresponding policy. ... The former allies disagreed on many issues, but the chief source of conflict was the ... The containment of Communism had to be worldwide, because American

Explanation:

PLEASE PLEASE PLEASE HELP THE QUESTION IS IN THE PICTURE

Answers

The answer should be c

(WILL GIVE BRAINLIEST)
What are some of the subtle ways prejudice shows itself in my life?
• How does it affect me when I am intolerant of others?
• How does it affect me when I am respectful of differences in other people?
• How can I respect the ways in which I am different from others, and how does it affect me when I cannot do this?
• How might my respect for my own differences impact my life and my relationships with others?

Answers

Answer:

Explanation:

•  ( being intolerant means you're unwilling to tolerate other ideas, opinions, beliefs or cultures)(question 1)

•( Respecting both similarities and differences in others opens doors to many opportunities.You'll learn new things and make better decisions, which in turn will help your career and improve your self-confidence.)(question 2)

•(Be courteous and friendly to others. ...

Make a family book about similarities and differences:

Value difference. ...

Meet new friends. ...) (question 3)

• (Just like with yourself, when you demonstrate respect for others, you give value to their being and ideals. In addition, you'll make someone feel good by granting them respect, provided, of course, that it's something that they deserve.)(question 4)

Hope this helps :)

Loud music from a neighbor's party is: Group of answer choices a negative externality whether or not you like it. a positive externality whether or not you like it. a positive externality if you like the music, and a negative externality if you don't. a negative externality if you like the music, and a positive externality if you don't. not an externality.

Answers

Answer:

a positive externality if you like the music, and a negative externality if you don't.

Explanation:

Positive externality: The term "positive externality" is described as the benefits that are being enjoyed by individuals outside the marketplace because of a specific firm's actions yet for which they don't pay any particular amount.

Negative externality: The term "negative externality" is described as the "negative consequences" that are being faced by outsiders because of a particular firm's actions to which nothing is charged by a market.

In the question above, loud music could be a positive externality if someone likes the music whereas negative externality if someone doesn't like it.

What was the purpose of the Friedman’s bureau

Answers

Answer:

On March 3, 1865, Congress passed "An Act to establish a Bureau for the relief of freedman and refugees" to provide food, shelter, clothing, medical services, and land to displaced southerners, including newly freed African Americans.

Explanation:

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