Question

question 3
one map unit is equivalent to which of the following values?
the physical distance between two linked genes
1% frequency of recombination between two genes
1 nanometer of distance between two genes
the distance between a pair of homologous chromosomes

Explanation:

In genetics, a map unit (also called a centimorgan) is defined as 1% frequency of recombination between two genes. Recombination frequency is used to map the relative positions of genes on a chromosome. Physical distance (like nanometers) is not how map units are defined. Also, it's not about the distance between homologous chromosomes. Map units specifically relate to recombination frequency between linked genes.

Answer:

1% frequency of recombination between two genes