Which unit of organisms evolves- an individual, a population, or a species? explain.

A population, because the individuals in a population will interbreed with mutations, and with time the mutations will breed and evolve.

a species

explanation: when darwin studied the birds in that one island he found that there were DIFFERENT species of the bird they evolved to fit their needs such as the beaks were shorter or smaller depending on what each species of the bird ate mostly

the element that provides strength to the exoskeletons of clams and oysters is phosphorus. this is so because calcium carbonate is the main component in the shells.

explanation:

answer; both surfaces of the membrane are nonpermeable