2. How does oxygen and carbon availability affect cellular respiration?
A. Both are needed as a reactant of
cellular respiration.
B. Neither are a product of cellular
respiration.
C. Oxygen is only needed for these processes.

i would say A. Both are needed as a reactant of cellular respiration.

Explanation:

While water is broken down to form oxygen during photosynthesis, in cellular respiration oxygen is combined with hydrogen to form water. While photosynthesis requires carbon dioxide and releases oxygen, cellular respiration requires oxygen and releases carbon dioxide. ... Without oxygen, much less ATP would be produced.Aug 31, 2018

the corpus luteum secretes estrogens and progesterone. the latter hormone causes changes in the uterus that make it more suitable for implantation of the fertilized ovum and the nourishment of the embryo. if the egg is not fertilized, the corpus luteum becomes inactive after 10–14 days, and menstruation occurs.

i hope this : )