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 diploid number of chromosomes is sometimes represented by the symbol 2n. for the fruit fly, the diploid number is 8, which can be written as 2n = 8, where n represents twice the number of chromosomes in a sperm or egg cell.

i might be wrong but i think its a. let me know if i’m right and have a good rest of your day!