What would you compare red blood cells to? why? a house
a school
the human body
a city
a car

Explanation:

On a peripheral blood smear, normal RBCs are disc-shaped with a pale-staining central area called the central pallor. When judging red cell size on a blood smear, the classic rule of thumb is to compare them to the nucleus of a small normal lymphocyte. The normal lymphocyte nucleus has an approximate diameter of 8 µm.

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.