Where do steroids come from or how is it made?

Testosterone was first synthesized in Germany in 1935 and was used to medically treat depression.

Hundreds of steroids are found in plants, animals and fungi. All steroids are manufactured in cells from the sterols lanosterol (opisthokonts) or cycloartenol (plants). Lanosterol and cycloartenol are derived from the cyclization of the triterpene squalene.

Iwould put 'think' in the blank