Author Question: Earth's first atmosphere was rich in water vapor but poor in free oxygen. The atmosphere became more ... (Read 75 times)

Pineapplelove6

  • Hero Member
  • *****
  • Posts: 560
Earth's first atmosphere was rich in water vapor but poor in free oxygen. The atmosphere became more oxygenated with the
 
  A) development of the ozone layer.
  B) emergence of stromatolites that developed a simple version of photosynthesis.
  C) emergence of gases from volcanic eruptions.
  D) both A and B.

Question 2

What was the one most important event in the Precambrian?
 
  What will be an ideal response?



flexer1n1

  • Sr. Member
  • ****
  • Posts: 373
Answer to Question 1

Answer: B

Answer to Question 2

Answer: The accumulation of free oxygen in the atmosphere. This allowed the ozone layer to form and allowed life to emerge.



Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question
 

Did you know?

Blood is approximately twice as thick as water because of the cells and other components found in it.

Did you know?

In the ancient and medieval periods, dysentery killed about ? of all babies before they reach 12 months of age. The disease was transferred through contaminated drinking water, because there was no way to adequately dispose of sewage, which contaminated the water.

Did you know?

All adults should have their cholesterol levels checked once every 5 years. During 2009–2010, 69.4% of Americans age 20 and older reported having their cholesterol checked within the last five years.

Did you know?

Many of the drugs used by neuroscientists are derived from toxic plants and venomous animals (such as snakes, spiders, snails, and puffer fish).

Did you know?

Drug-induced pharmacodynamic effects manifested in older adults include drug-induced renal toxicity, which can be a major factor when these adults are experiencing other kidney problems.

For a complete list of videos, visit our video library