Metamorphosis is a type of homeostasis. A. is the correct answer.
The correct answer is a dichotomous key. Basically, you use the key to decide what species an organism is by looking at what traits it has, and if it doesn't have some traits you can instantly rule out a large number of species which brings you closer to your answer of what the species is that you're looking at.
B. subtract the frequency of the recessive allele from 1.
There are two main reasons why cells divide rather than continuing to grow larger and larger. One of the main reason is that the larger cell become more demanding, therefore the large cell will increase load on the machinery of the cell such as DNA. The other reason is that if the cell grow too large it will be difficult for the cell to move for nutrients and discard the waste across the cell membrane. Also the surface area for each cell will also be reduced, which is required for active functionality of a cell.
The red blood cell does not have a nucleus. The lack of nucleus enables the rbc to have more room to contain hemoglobin which increases it's efficiency to carrying oxygen