Which part of the eye focus light rays on the retina?
a. lens
b. pupil
c. sclera
d. iris

The right answer is A. lens

The eye-lens is a natural convergent lens of the eye.

The eye has two natural convergent lenses: the cornea, located at the entrance of the eye, and the crystalline, biconvex lens located behind the iris and connected to the envelopes of the eye by the ciliary body. These two lenses focus the light rays on the retina, which acts as a screen in the back of the eye.

answer: the blood-brain barrier is a layer of specialized membranes and cell processes designed to keep undesirable substances from passing from the bloodstream into the precious tissues of the brain. while the blood-brain barrier does keep most bad things out of the central nervous system, it is not impermeable.

explanation:

for 8 am not sure maybe yes?

for 9 if it is asking if the male is more or less it would be less

hope i even just a little : )