Which of the Following Explains a Reason Why Chromosome Abnormalities

Multiple Choice

Which of the following explains a reason why chromosome abnormalities occur?

A) Chromosomes do not separate properly in meiosis.
B) The processes of mitosis and meiosis get reversed.
C) Environmental influences cause a zygote to form without the fusion of a sperm and egg.
D) None of these can explain why chromosomal abnormalities occur.