Genetic variation happens when one organism in the population mates with a genetically different organism. Same species, different genetics such as color or height/weight.
Explanation:
under what circumstance does a negative cell presents An antigen to another negative cell
Explanation:
Observations allow us to collect data that we can connect back to the central problem. From this data we can start to form hypotheses (predictions on possible solutions or outcomes).
A dominant trait will mask a recessive trait.