Question

a researcher wants to establish, in a laboratory, a population of flies that is in hardy-weinberg equilibrium. to this end, which statement should the researcher be sure is true regarding this fly population?
the fly population must be remarkably large in size (i.e., \infinite\).
the fly population must experience either gene flow or genetic drift.
individual flies within this population must not be able to mate randomly.
natural selection can be acting upon this fly population.

Explanation:

Hardy-Weinberg equilibrium requires no genetic drift, which is minimized in large populations (approximating "infinite" size). The other options violate equilibrium conditions: gene flow/drift, non-random mating, and natural selection all disrupt allele frequency stability.

Answer:

A. The fly population must be remarkably large in size (i.e., "infinite").