How many alleles can exist for a given gene in a population?

• A. Two
• B. One
• C. None
• D. Multiple

Answer: (D)

Verified step by step guidance

1. Understand that an allele is a variant form of a gene. Different alleles can result in different traits or characteristics.
2. Recognize that in a population, a gene can have multiple alleles. This is due to mutations and genetic variations that occur over time.
3. Consider the example of the ABO blood group system in humans, which is determined by multiple alleles: A, B, and O.
4. Realize that while an individual can only have two alleles for a given gene (one from each parent), a population can have many more alleles.
5. Conclude that the correct answer is 'Multiple' because a population can have multiple alleles for a given gene, contributing to genetic diversity.