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

Did the Mongols invaded Korea known as Gloria all the time on several occasions between the year 1231 and 1270 which statement is true of those invasions

Answers

don’t believe the person above me it’s a scam . it’s also annoying i’m sorry about that

Adler owes Perreault, a police captain, $500. Adler threatens Perreault that unless Perreault gives him a discharge from the debt, Adler will disclose the fact that Perreault has on several occasions become highly intoxicated and has been seen in the company of certain disreputable persons. Perreault, induced by fear that such a disclosure would cost him his position or in any event lead to social disgrace, gives Adler a release but subsequently sues to set it aside and recover on his claim. Will Adler be able to enforce the release

Answers

Answer:

No Alder will not be able to enforce the release

Explanation:

In the given scenario Alder is trying to use duress and blackmail techniques to force Perreault to release him from his debt obligations.

However Perreault induced by fear gives Adler a release but subsequently sues to set it aside and recover on his claim.

Alder will not be able to enforce the release because it was obtained under duress.

Under contract law the release is not valid.

What is an “Unrestricted Submarine Warfare”? ( In your own words )

Answers

Answer:

You literally should be able to tell by context.... it's what it sounds like...

Explanation:

Unrestricted submarine warfare is a type of naval warfare in which submarines sink vessels such as freighters and tankers without warning, as opposed to attacks per prize rules (also known as "cruiser rules").

Which diagram most effectively shows how a voter influences policy?
A.
A voter decides
her vote doesn't
make a
difference.
She doesn't vote,
and the current
mayor is
reelected.
B.
A voter serves
on a jury.
He decides he
has an opinion
about the death
penalty in his
state.
C.
A voter learns
about national
issues.
She makes an
informed choice
to vote for a
candidate she
agrees with
D.
A voter registers
to vote
He increases his
local voter
tumout slightly.

Answers

Answer:

c

Explanation:

The option that shows how a voter influences policy is option c. A voter learns  about national  issues She makes an  informed choice  to vote for a  candidate she  agrees with.

The voter in an election is a person who has the power to choose who her representatives in the government should be.

When a citizen votes for a particular person they vote based on the fact that they agree with the political ideology of the person.

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A physical anthropologist studies the _____ of human remains.


phenology

physical characteristics

physiology

physics

Answers

A physical anthropologist studies physiology of human characteristics

Answer:

A physical anthropologist studies the forensics of human remains.

Explanation:

why did many people believe that declaration of independence justified an end to slavery

Answers

Because they thought that it would generally make a change to society, an most people will believe anything as long as it has a good source to go off of

how inefficient public participation can lead to a lack of ownership of community services?​

Answers

An inefficiency in public participation process can lead to different factors such as the loss of faith in the agency.

Note that a negative experience of this process can result in the participants having a form of negative perceptions of the outcome or result and so  they may not want to be involved or participate in any future processes.

What factors influence community participation?

There are a lot of  factors that affect this. They arise from financial, material reasons.

Others are due to tangible or non-tangible factors such as culture, history, government policy etc. that tends to affect the system and this can to a lack of ownership of community services.

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How did the Inca govern their empire successfully?

Answers

Answer:

by planing ahead of there empire

Explanation:

99% sure

Which are types of income tax that people pay? Check all that apply.
federal
local
progressive
state
sales
flat

Answers

Answer:

Federal, Local, State

Federal, Local, and State

Nora has a quick temper, overreacting in anger every time one of her classmates does something she doesn't like. Her teacher suggests that whenever another student annoys her, she should (1) stop to decide what behavior in particular is bothering her, (2) think about several possible ways of responding to the behavior, and (3) choose the response that is most likely to be both productive and prosocial. In self-regulation terminology, the teacher is trying to promote ________ in Nora.

Answers

Explanation:

How she can control her anger

PLSS HELPPP me think of an essay title....What is a good title for an essay about anti asian hate crimes and violence like i can't think of a title that is convincing, descriptive and captivating

Answers

Answer:

Stop Asian and violence

Explanation:

Answer:

A Rising Tide of Hate and Violence against Asian Americans ...

Explanation:


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:

an is a strong visual learner. In his violin performance class, Ian is required to take a test that involves playing two songs from memory. Which strategy would most likely help Ian prepare for his test

Answers

Answer:

I think Practice makes perfect, If he plays it or listens to it enough he will remember and be able to do it

Explanation:

Select which options below are responsibilities

Question 5 options:

Pay taxes


Serve in court


Participate in your community


Respect the rights and property of others

Answers

Answer:

pay taxes and serve in court

Explanation:

The given options act as responsibility in paying taxes. Thus, option A is correct.

What do you mean by responsibilities?

Responsibilities are authority or engagement for taking any decision and paying attention at work for better utilization of resources and efficiency of work.

When the government of a nation collects money from its residents as a tax, it is used to fund various aspects of the nation's growth, such as the construction of hospitals, roads, and transit systems.

Given that the other options lack any indication of authority or standards for making decisions, which are necessary to articulate the characteristics of responsibility, only option A makes things relatable to the given situation.

Therefore, option A paying taxes is appropriate.

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How did the Brown v. the Board of Education ruling impact North Carolina public schools? It called for the desegregation of all public schools. It maintained the legality of segregation in public schools. It required students to attend the school closest to them. It provided funding for busing to speed up desegregation.

Answers

Answer:

The Supreme Court's decision in Brown v. Board marked a shining moment in the NAACP's decades-long campaign to combat school segregation. In declaring school segregation as unconstitutional, the Court overturned the longstanding “separate but equal” doctrine established nearly 60 years earlier in Plessy v.

Explanation:

hope this helps

The Brown v. Board of Education decision has an impact on North Carolina public schools since it mandates the desegregation of all public schools. Thus, option A is correct.

What is Brown v. the board of education?

The United States Supreme Court found completely that segregated schools were a violation of the Constitution's Fourteenth Amendment, which bans states from refusing equal treatment to anybody within their authority.

In the judgment given by the supreme court, it was found that segregated school facilities are unequal for white and African American children.

Therefore, option A desegregation of public schools is correct.

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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!!!!

Which of the following statements is false? a. ​Probation officers write presentence reports to help judges decide sentences. b. ​Probation and parole officers have the authority and power to recommend revocation. c. ​Parole officers generally deal with younger, less- serious offenders than probation officers. d. ​Parole board members or their designees make decisions regarding release.

Answers

Answer:

d. ​Parole board members or their designees make decisions regarding release.

Explanation:

A probation officer is in charge of writing presentence reports to help judges decide sentences.

Accordingly, a probation and parole officer have the authority and power to recommend revocation.

Parole officers generally deal with younger, less- serious offenders than probation officers.

Therefore, the wrong statement from the given answer choices is option D which says that parole board members or their designees make decisions regarding release which is false as it is the job of parole boards to make decisions regarding

discretionary parole

Explain what political system are

Answers

Answer:

In political science, a political system defines the process for making official government decisions. It is usually compared to the legal system, economic system, cultural system, and other social systems.

Answer:

its mean to make decision by government

PLS HELP ME I WILL GIVE 20 POINTS!!! and Brainliest
Ramses 2 is rememberer for ________ .Select ALL that apply.

a
constructing temples throughout ancient Egypt.
b
restoring the glory and power of ancient Egypt.
c
conquering the regions of Canaan and Syria.
d
reorganizing the Egyptian system of government.

Answers

Answer:

c

Explanation:

¿Es lo mismo ser inmoral que ir contra la ética? porfavor ayuda...

Answers

La respuesta correcta para esta pregunta abierta es la siguiente.

A pesar de que no anexaste opciones o incisos para responder, podemos comentar lo siguiente.

¿Es lo mismo ser inmoral que ir contra la ética?

No, no es lo mismo.

Ser inmoral significa que una persona, lugar, comportamiento o expresión va en contra de los valores morales convencionales dentro de una sociedad, y por tanto, es grosero, de mal gusto, atenta contra los principios básicos de la decencia, la familia, o las buenas costumbres.

En el caso de "ir contra la ética," se puede hablar de comportamientos, posturas o decisiones que son cuestionables por su intención y no se apegan a "lo que es correcto." Puede tratarse de mentiras, engaños, o manipulaciones.

Why are the average temperatures in the middle of the United States warmer than the coasts?

Answers

Answer:

The reason for the difference in weather is that Detroit and Miami have very different climates. Many factors, such as elevation, ocean currents, distance from the sea, and prevailing winds, can affect the climate of an area. One of the most important things that influences climate, though, is latitude.

Explanation:

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:

Exam
In Western Europe from 1000-1300
CE, which of the following occurred for
the farming community?
A. Towns began to grow in Europe.
B. Crop rotation was developed.
C. Working guilds were formed in cities.

Answers

In Western Europe from 1000-1300 CE, Crop rotation was developed.

What happened in Western Europe from 1000-1300 CE?

Between the years 1000 and 1300, there was agricultural revolution in Europe, which implies crop yields increased in multiple folds. A host of new agricultural technologies and techniques spread across Europe.

Climate change in the period 1000-1300 led to many changes for Europe in the Medieval Warm Period. Explore the agricultural revolution, political climate change, new technologies for farming and horses, and the implementing of three-field crop rotation.

Another event that follow suit is the population increase, tripling in less than three centuries. The average European lifespan increased by as much as two decades. Towns and cities re-emerged, and with them came new crafts and a revival of trade. New classes of merchants and craftsmen attained some degree of social mobility.

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What does M.A.N.I.A stand for? *

Answers

Answer:

M.A.N.I.A to help students remember the 5 major causes of WWI; they are Militarism, Alliances, Nationalism, Imperialism, and Assassination.

Explanation:

Answer:Militarism, Alliances, Nationalism, Imperialism, and Assassination is what M.A.N.I.A stand for.

Where would you find a tropical maritime air mass?

Answers

Answer:Maritime tropical air masses that affect the United States originate in the Caribbean Sea, southern Gulf of Mexico, and tropical Atlantic east of Florida through the Bahamas. Monsoon air masses are moist and unstable. Superior air masses are dry, and rarely reach the ground.

Explanation:

Do you think it's necessary or even important for people to have kids

Answers

Raising kids is one of the toughest and most fulfilling jobs in the world — and the one for which you might feel the least prepared
You can't expect kids to do everything simply because you, as a parent, "say so." They want and deserve explanations as much as adults do. If we don't take time to explain, kids will begin to wonder about our values and motives and whether they have any basis. Parents who reason with their kids allow them to understand and learn in a nonjudgmental way.

who were the city of gods

Answers

Answer: Teotihuacán

Explanation: Have a good day :)

Teotihuacán ! hope this helps! brainliest??

Which of the social, economic or educational philosophy are you most thankful for? What do you think will our modern life be like without that idea?

Answers

Answer:

These educational philosophical approaches are currently used in classrooms the world over. They are Perennialism, Essentialism, Progressivism, and Reconstructionism. These educational philosophies focus heavily on WHAT we should teach, the curriculum aspect.


Discuss why entrepreneurship could be a good option for an
unemployed person.

Answers

Answer:

it opens doors to new ventures, new business, new alliances etc. They also provide employees with the means to further grow one's own earning potential through training and on-the-job experience

In what decade did a new amendment to the United States Constitution broaden the definition of citizenship?

A The 1840s
B The 1850s
C The 1860s
D The 1870s

Answers

Answer:

60s

Explanation:

I'm pretty sure its the 60s mabye the 70s

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