What exactly are anabolic steroids? what are they, how do they work in the body, and which sports people use them?

They are chemicals: that are produced by the body, more in males than in females, including testosterone and a bunch of similar steroid molecules (like DHEA), which increase during puberty in males (less so in girls) to increase muscle mass, change distribution of fat/muscle, and cause sexual maturation. Synthetics have been made that mostly increase muscle mass. They are dangerous &cause liver and mental problems.