Answer:
Independent Variable: Give one group the drug and dont give the other group the drug
Dependent Variable:The data of if the drug improves the rats memory(if their memory is better, the same, or made worse)
If it is always expressed it is dominant, also dominant allele is a possible answer. If it is not expressed unless both alleles are the same, it is recessive.
I think the correct answer among the choices listed above is option B. The process that creates specialized cells like blood cells, nerve cells, or bone cells, is called differentiation. It is a process where generic embryonic cells become specialized cells.