Which conditions are necessary for natural selection? Check all that apply.
Populations do not have genetic variation.
Populations have genetic variation.
The environment changes.
The environment stays the same.
Organisms must have specific traits in order to survive and reproduce.
O Organisms with any traits will survive and reproduce.

The answer is B, C,E

The nuclear potential that binds protons and neutrons in the nucleus of an atom is often approximated by a square well. imagine a proton conned in an innite square well of length 105 nm, a typical nuclear diameter. calculate the wavelength and energy associated with the photon that is emitted when the proton undergoes a transition from the rst excited state (n 2) to the ground state (n 1). in what region of the electromagnetic spectrum does this wavelength belong?