Answer:
A. Conduct impulses faster.
Explanation:
Myelinated axons are called that way due to the myelin sheath that surrounds them. Myelin has an insulation property so electrical impulses cannot travel through it, except on certain sites called Nodes of Ranvier. In order for electrical impulses to be conducted on myelinated axons they must "jump" from one Node of Ranvier to the next, and thus conduction is faster. This is called saltatory conduction.
The factors that affect personal health that are the most easily controlled are c) lifestyle.
You can easily change the way you are living, whereas these other things cannot be.
Answer:
B) a nonsense mutation; this is because a nonsense mutation results in the change of a regular amino acid codon into a stop codon, which ceases translation. This fits with the problem's description of the protein that causes the symptoms as too short, as translation is the process by which proteins/polypeptides are created. A missense mutation would not be the answer because it still codes for an amino acid, which would not shorten the protein. A duplication of the gene would probably just lengthen the protein or not affect its length at all.
