What is the meaning of life

Need , i need a scenario of: artificial selectionmutationnon random mating

All of these things can block a bronchus and cause collapse of a lung except

Nitrogen-14 and nitrogen-15 are isotopes of the same element. how do these two isotopes differ? a. they have different numbers of nuclei. b. they have different numbers of protons. c. they have different numbers of neutrons. d. they have different numbers of electrons.