C...the key is that they are photosynthetic...so they produce oxygen (like plants)!
While stopping to get gas in The Valley of Ashes, Nick notices the eyes of whom staring down at them? (hint: there are 2 pairs of eyes watching)
More negatively charge than the outside.
Answer:
the answer would be the 3rd answer
Explanation:
a half life is the time it takes for half of a radioactive substance to decay
I hope this helps :)