3. the opening that allows light to enter the eye is the
a. iris
b. pupil
c. optic nerve
d. vitreous humor

A)  Iris

Explanation:

The Iris controls the diameter of the opening in your eye, thus also controlling the amount of light let inside. It's also reponsible for the colour of you eye.

A. The opening that allows light to enter the eye is the iris.

Explanation:

answer

fusion: the energy source of stars. the energy released from the collapse of the gas into a protostar causes the center of the protostar to become extremely hot. when the core is hot enough, nuclear fusion commences. fusion is the process where two hydrogen atoms combine to form a helium atom, releasing energy.

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