Answer:
Cystic fibrosis mutation is recessive to normal allele because only one functional or normal allele is enough to produce a functional protein. So, if mutation is present in one allele then also, a normal protein can be made from normal allele. The presence of normal protein prevents the expression of disease.
In addition, mutated allele only results in the loss of function of protein which can be compensated by the expression of normal allele. It does not add any toxic effect to the protein. Consequently, the disease is inherited in autosomal recessive fashion.
In contrast, Huntington mutation not only alters the structure of the functional protein but also adds toxicity to it. The altered protein is enable to interact with 100s of other proteins and inhibit or decrease their function. So, if only one allele is present then also, the mutated protein will be produced and it will result in the phenotype. Consequently, it is inherited as autosomal dominant fashion.
A
B is wrong because mitochondria would likely absorb the stain even if it was dead.(And most cells that have been treated are dead anyway). C and D are just throwaway answers, you usually want to avoid the word "always" when drawing conclusions.
Answer:
if mitosis is unregulated, cancer cells could multiply continuously or create defective daughter cells.
