× Didn't find what you were looking for? Ask a question
Top Posters
Since Sunday
w
3
w
3
e
3
3
r
3
g
2
2
b
2
M
2
V
2
f
2
c
2
Home Q & A Board Science-Related Homework Help Geography and Earth Sciences
New Topic  
merandaae19 merandaae19
wrote...
Go to Answer
Posts: 764
Rep: 0 0
6 years ago

The primary source for free oxygen introduced into the atmosphere during the Proterozoic was through
  photosynthesis.
  a. True
  b. False
Read 61 times
1 Reply
Replies
Answer verified by a subject expert
scatherinescatherine
wrote...
#1
Top Poster
Posts: 622
Rep: 4 0
6 years ago
Sign in or Sign up in seconds to unlock everything for free
1

Related Topics

merandaae19 Author
wrote...

6 years ago
Correct Slight Smile TY
courtneyrmcd
wrote...

Yesterday
Helped a lot
lierac00
wrote...

2 hours ago
You make an excellent tutor!
New Topic      
Quick Reply
Explore
Post your homework questions and get free online help from our incredible volunteers
  1286 People Browsing
Start New Topic Take the Tour CoursesNew Study Tools Topics Trending Browse by Textbook
Live Chat
Related Images
  
 1427
  
 345
  
 125
Your Opinion
What's your favorite coffee beverage?
Votes: 305
Previous poll results: Should Ph.D.'s be addressed as doctors?