Answer:
They slowly lose energy.
Explanation:
High-energy electrons give the chain either NADH or FADH2 to complete it.
Low-energy electrons form water by decreasing the oxygen molecules.
The answer is A. Environmental conditions are not always right to produce flowers and seeds for sexual reproduction.
Most plants are able to reproduce either way because even if the conditions aren't right for the plant, it can still make more flowers so it doesn't die out.
I hope this helps! :D