a.

Retina

b.

Optic nerve

c.

Cornea

d.

Iris

a.

Reluctance to start moving once at rest, and it's reluctance to stop moving once it has begun to move

b.

Reluctance to stop moving

c.

Readiness to start moving

d.

Reluctance to start moving and it's readiness to stop moving once it has begun to move

a.

Zero

b.

Negative

c.

Positive

d.

Average

a.

Gamma rays, ultraviolet rays, X-rays, infra-red rays

b.

Infra-red rays, ultraviolet rays, X-rays, Gamma rays

c.

Gamma rays, X-rays, ultraviolet rays, infra-red rays

d.

Gamma rays, ultraviolet rays, infra-red rays, X-rays