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 39 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
YES! Correct, THANKS for helping me on my review

Dominic

  • Member
  • Posts: 328
Reply 3 on: Yesterday
Gracias!

« previous next »
 

Did you know?

No drugs are available to relieve parathyroid disease. Parathyroid disease is caused by a parathyroid tumor, and it needs to be removed by surgery.

Did you know?

Long-term mental and physical effects from substance abuse include: paranoia, psychosis, immune deficiencies, and organ damage.

Did you know?

Blastomycosis is often misdiagnosed, resulting in tragic outcomes. It is caused by a fungus living in moist soil, in wooded areas of the United States and Canada. If inhaled, the fungus can cause mild breathing problems that may worsen and cause serious illness and even death.

Did you know?

Eating carrots will improve your eyesight. Carrots are high in vitamin A (retinol), which is essential for good vision. It can also be found in milk, cheese, egg yolks, and liver.

Did you know?

Congestive heart failure is a serious disorder that carries a reduced life expectancy. Heart failure is usually a chronic illness, and it may worsen with infection or other physical stressors.

Mira as seen from the Earth Mira as seen from the Earth
Levels of Prevention Levels of Prevention
Young adulthood brings the greatest number of role transitions and highest levels of demands than ... Young adulthood brings the greatest number of role transitions and highest levels of demands than ...
Composition of the Atmosphere Composition of the Atmosphere
Coastal sensitivity to rising sea levels Coastal sensitivity to rising sea levels
The Distribution of Water on Earth The Distribution of Water on Earth
Video: Brief Summary on Photosynthesis - Animation

For a complete list of videos, visit our video library