A Wild Mouse Population Has Coexisted for Millions of Years

question 103

Multiple Choice

A wild mouse population has coexisted for millions of years with Toxoplasma parasites.However, during a recent year, the mouse population was almost decimated by a Toxoplasma infection.What factor most likely explains this sudden change in the pattern of coexistence?

• A) A new, more virulent strain of Toxoplasma emerged.
• B) The existing Toxoplasma strain became more virulent.
• C) The existing Toxoplasma strain began to reproduce more rapidly.
• D) The mouse population became more susceptible to the original Toxoplasma parasite.
• E) The mouse population became less susceptible to the original Toxoplasma parasite.

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Definitions:

Albino

An individual lacking normal pigmentation due to a genetic condition that affects the production of melanin in the skin, hair, and eyes.

Homozygous

State of having identical allelic genes at one or more paired loci in homologous chromosomes.

Pigmentation

The coloring of a person's skin, hair, or eyes due to the deposition of melanin, a natural pigment produced by certain cells called melanocytes.

Incomplete Dominance

A genetic phenomenon where the phenotype of a heterozygote is intermediate between the phenotypes of the two homozygotes.