Which of the following is true of spermatogenesis?
a. occurs before puberty
b. involves the differentiation of spermatids leading to the formation of mature spermatozoa
c. the process of spermatozoa production
d. results in the production of primary spermatocytes
e. involves the production and secretion of testosterone

The correct answer is c. the process of spermatozoa production

Explanation:

Spermatogenesis is the process of formation of sperms in the seminiferous tubules present in the testes. The process of spermatogenesis starts when germ cells present in the seminiferous tubule starts dividing mitotically.

Some of these cells become primary spermatocytes after mitosis and enters meiosis I. After completion of meiosis I they become secondary spermatocytes.

Each secondary spermatocytes converts into two haploid spermatids after completion of meiosis II. Spermatids then differentiate into mature sperms called spermatozoa.

Thus, the correct answer is c.  the process of spermatozoa production

answer: the blood-brain barrier is a layer of specialized membranes and cell processes designed to keep undesirable substances from passing from the bloodstream into the precious tissues of the brain. while the blood-brain barrier does keep most bad things out of the central nervous system, it is not impermeable.

explanation:

the answer is lactic acid from anaerobic respiration. the acid in lactic acid is what creates sore and burning muscles. if you think about how acid burns that will give you a clue for questions like this.