Which observation proves that a cell is a eukaryote?

a: it contains cytosol

b: it has a nucleus

c it has a cytoskeleton

d: it has a cell membrane

B

Explanation:

It has to have a nucleus to be a eukaryotic cell.

option a is correct i.e.

explanation:

in context to the membrane of nerve impulse, the outer membrane of neuron is semi permeable that is only sodium ions can pass through the membrane i.e. smaller ions can pass through the membrane while larger ions cannot pass through it.