Chromatids are ____________________

Question

Chromatids are ____________________.  
A) attached at the centriole.
B) a pair of chromosomes, one from the mother and one from the father
C) attached to the nuclear envelope
D) identical before and after crossing over occurs.
E) identical until crossing over occurs

Accepted Answer

Chromatids are identical before crossing over occurs because they are the result of DNA replication, but they can undergo crossing over during meiosis, resulting in genetic diversity.