This topic contains a solution. Click here to go to the answer
« previous next »

Author Question: How long did it take for oxygen to build up in the Earth's atmosphere to its present levels? A) ... (Read 65 times)

809779

  • Hero Member
  • *****
  • Posts: 579
on: Jul 27, 2018
How long did it take for oxygen to build up in the Earth's atmosphere to its present levels?
 
  A) at least 542 million years
  B) at least 360 million years
  C) at least 2 billion years
  D) at least 3.5 billion years

Question 2

Express the following number to three significant figures: 21.25 m
 
  What will be an ideal response?


Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question
Marked as best answer by a Subject Expert

blakeserpa

  • Sr. Member
  • ****
  • Posts: 338
Reply #1 on: Jul 27, 2018
Answer to Question 1

C

Answer to Question 2

21.3 m


809779

  • Member
  • Posts: 579
Reply 2 on: Jul 27, 2018
Thanks for the timely response, appreciate it

bassamabas

  • Member
  • Posts: 294
Reply 3 on: Yesterday
Gracias!

« previous next »
 

Did you know?

Pregnant women usually experience a heightened sense of smell beginning late in the first trimester. Some experts call this the body's way of protecting a pregnant woman from foods that are unsafe for the fetus.

Did you know?

Alcohol acts as a diuretic. Eight ounces of water is needed to metabolize just 1 ounce of alcohol.

Did you know?

Approximately 500,000 babies are born each year in the United States to teenage mothers.

Did you know?

Astigmatism is the most common vision problem. It may accompany nearsightedness or farsightedness. It is usually caused by an irregularly shaped cornea, but sometimes it is the result of an irregularly shaped lens. Either type can be corrected by eyeglasses, contact lenses, or refractive surgery.

Did you know?

Patients should never assume they are being given the appropriate drugs. They should make sure they know which drugs are being prescribed, and always double-check that the drugs received match the prescription.

Earth Earth
The Distribution of the Earth's Wealth The Distribution of the Earth's Wealth
Heaven or earth? Heaven or earth?
Gases in the Atmosphere Gases in the Atmosphere
The Oceans of Earth The Oceans of Earth
Levels of Structural Organization & Body Systems Levels of Structural Organization & Body Systems
Video: A Human Karyotype Preparation Animation

For a complete list of videos, visit our video library