Can O and N form a covalent bond?

Asample of the male sex hormone testosterone, c19h28o2, contains 3.88×10^21 atoms of hydrogen.(a) how many atoms of carbon does it contain? (b) how many molecules of testosterone does it contain? (c) how many moles of testosterone does it contain? (d) what is the mass of this sample in grams?

Acontrol during an experiment. might change remains constant does not exist does change

Which factor is likely to impact the possible number of compounds ?