C.
A is incorrect because if they have the disease then they cannot be healthy.
B is incorrect because if the genetic disease is recessive then the cannot have the homozygous mutated gene because then it would mean that they are ill.
D is incorrect because having an offspring that is ill doesn't always guarantee that all the offspring will be ill. <span />
Because the weight is evenly distributed
Mylenation - an insulator along the axon
