A primary spermatocyte is a diploid cell that gives rise to two secondary spermatocytes after the first meiotic division. The primary spermatocyte has

b. the carbon cycle ensures living things have a source of hydrogen

only about ten percent of the energy at one trophic level is passed on to organisms at the next trophic level. the remainder of the energy is used in life processes or lost as heat.

the answer is d p: cell, q: organ, r: organ system, s: tissue

answer; endometriosis;