The cells that are formed during spermatogenesis by the first meiosis are called:.
1. spermatozoa.
2. spermatogonia.
3. primary spermatocytes.
4. secondary spermatocytes.
5. spermatids.

frogs. the lower the ph the higher the acid content. frogs have the highest tolerance in this scenario.

many other transport proteins, often called pumps, move materials against a concentration gradient. active transport drives molecules across a membrane from a region of lower concentration to a region of higher concentration. this process, shown in figure 5.1, uses transport proteins powered by chemi- cal energy.

a metamorphic rock would be formed.