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 31 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
:D TYSM

samiel-sayed

  • Member
  • Posts: 337
Reply 3 on: Yesterday
Great answer, keep it coming :)

« previous next »
 

Did you know?

The first documented use of surgical anesthesia in the United States was in Connecticut in 1844.

Did you know?

Signs and symptoms of a drug overdose include losing consciousness, fever or sweating, breathing problems, abnormal pulse, and changes in skin color.

Did you know?

Over time, chronic hepatitis B virus and hepatitis C virus infections can progress to advanced liver disease, liver failure, and hepatocellular carcinoma. Unlike other forms, more than 80% of hepatitis C infections become chronic and lead to liver disease. When combined with hepatitis B, hepatitis C now accounts for 75% percent of all cases of liver disease around the world. Liver failure caused by hepatitis C is now leading cause of liver transplants in the United States.

Did you know?

Inotropic therapy does not have a role in the treatment of most heart failure patients. These drugs can make patients feel and function better but usually do not lengthen the predicted length of their lives.

Did you know?

According to the Migraine Research Foundation, migraines are the third most prevalent illness in the world. Women are most affected (18%), followed by children of both sexes (10%), and men (6%).

Levels of DNA packaging to create a chromosome Levels of DNA packaging to create a chromosome
Speed of Earth Speed of Earth
The Tilt of Earth’s Axis The Tilt of Earth’s Axis
Planets, Earth and Moon Planets, Earth and Moon
Uncover the back down to the waist. Stand at the head to apply lubricant to the back using long ... Uncover the back down to the waist. Stand at the head to apply lubricant to the back using long ...
How to calculate present value (Question 4) How to calculate present value (Question 4)
Video: Biological organic compounds

For a complete list of videos, visit our video library