One reason why anabolic steroids can imitate the hormone testosterone is because (1) anabolic steroids and testosterone both interact with the same cell receptors
(2) testosterone acts only on muscle cells
(3) females produce small amounts of the hormone testosterone
(4) an increase in testosterone in males using anabolic steroids increases male features

it’s 4 (an increase in testosterone in males unsung anabolic steroids increases male features

Explanation:

anabolic steroids and testosterone both interact with the same cell receptors

this protocol provides a detailed procedure for co-immunoprecipitation (co-ip) to identify protein–protein interactions.

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.