2) The signal to contract is distributed deep into the muscle fiber by the a) Sarcolemma
b) Sarcomere
c) Transverse tubules
d) Myotubules
e) Myofibrils

c) Transverse tubules

Explanation:

The transverse tubules (T tubulars) are called these channels because they cross the filament. A network of interconnecting rings, each of which encircles a myofibril, is the transverse tubular structure. It provides an essential pathway of contact between the fiber outside and the myofibrils.

Explanation:

From the given information:

Since the parent are normal; Let assume that their trait is Pp

The affected sister  will be recessive in nature, so the trait will be pp

Now, the husband who is the groom will be a carrier with a probability of 2/3 since her sister is affected.

Also, the wife will be carrying a heterozygous trait since she is normal as well.

However, using Hardy-Weinberg assumption:

q = 0.02

Recall that:

Thus,

2pq = 0.0392

Finally, the required probability that there will be an affected offspring amongst the family is: