The following events occur during either mitosis or meiosis or in both. Which only occurs in meiosis?
A nuclear envelope breaks down
B condensation of DNA
C pairing up of homologous chromosomes
D centromeres separate

Which of the following occurs most often in a population when genetic variation and overproduction are present? some organisms have a lower reproductive success than others. some organisms have a higher reproductive success than others. some organisms have no reproductive success. some organisms do not have genetic variation.

1. the is the thinnest part of the earth. 2. the is the thickest part of the earth. 3. what metals are mentioned in the text?

What feature of cell theory is best demonstrated in the image