Answer: was talking
Explanation:
this is the only one that sounds right
Oceans produce approximately 80 percent of the oxygen our planet needs to support animal life. Pollution that reaches the ocean through dumping, oil leaks, runoff, and other processes interferes with that oxygen production and poses a real threat to the oxygen content in our atmosphere. If the oxygen content decreases, it is likely that carbon dioxide will increase. This could have dramatic consequences for life as we know it.<span> </span>
D all of the above because if you type a word in the dictionary.com it will give you all of those
The second one, the word "after" requires a comma sometime after it.