I think it’s humans inhale oxygen because that would keep the body stable which is what homeostasis is
ITS CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
the double helix is hydrogen bonded through the bases only so the bases are inside the helix only
as adenine combines with thymine and guanine with cytosine
phosphate are in the exterior of it
sugar groups constitute the double helix.
Explanation:
The given reaction equation is as follows.
+ ___ 
As there is release of one hydrogen which shows that mass number has increase by 1 on the product side.
Therefore, particle 
must be added in order to balance the given reaction equation.
Hence, the complete reaction equation will be as follows.
