D. Or A. It’s between those two
Answer:
Positive selection involves targeting the desired cell population with an antibody specific to a cell surface marker (CD4, CD8, etc.). ... Negative selection is when several cell types are removed, leaving the cell type of interest untouched.
Essential amino acids cannot be made by the body. As a result, they must come from food. The 9 essential amino acids are: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.
A courtship dance or mating ritual hope this helped
Answer:
Gravity is what holds the planets in orbit around the sun and what keeps the moon in orbit around Earth. ... Gravity creates stars and planets by pulling together the material from which they are made. Gravity not only pulls on mass but also on light.