Which of the following statements is true of crossing-over?
a. crossing-over contributes to genetic diversity or variation.
b. the gene for eye color can be exchanged with the gene for hair color during crossing-over.
c. only one gene may be exchanged at a time during crossing-over.
d. crossing-over always results in a non-beneficial mutation.

Crossing-over contributes to genetic diversity or variation.

Crossing-over is when homologous* chromosomes exchange genes. This result in different gene combinations.

*A pair of matching chromosomes. They have the same genes but can have different versions.

the principle of segregation describes how pairs of gene variants are separated into reproductive cells. from his data, mendel formulated the principle of segregation. we now know that the segregation of genes occurs during meiosis in eukaryotes, which is a process that produces reproductive cells called gametes.