Humans Have 23 Pairs of Chromosomes and Chimps Have 24

question 19

Multiple Choice

Humans have 23 pairs of chromosomes and chimps have 24 pairs. How has this difference best been explained?

• A) Humans and chimps are not related.
• B) Chimps gained a chromosome during their evolution, which explains why they differ from humans.
• C) Humans and chimps share very little genetic material.
• D) Humans have one chromosome that is the result of a fusion of two chromosomes in our ancestors.

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Definitions:

Macula Lutea

A small, yellowish central area of the retina that is rich in cones and where visual acuity is highest.

Fovea Centralis

A small depression in the retina where visual acuity is highest.

Optic Disk

The spot in the eye where the optic nerve meets the retina, sometimes referred to as the blind spot.

Retina

A thin layer of tissue located at the back of the eye, containing cells sensitive to light that trigger nerve impulses that pass via the optic nerve to the brain, where a visual image is formed.