What is a protein that is the main component of the thick filaments in muscle fibers and is responsible for muscle contraction?
a. actin
b. myosin
c. actin and myosin
d. nerve and bone

What causes temperature extremes in the desert

Acertain species of fish can have either long or short fins. the allele for long fins is dominant over the allele for short fins. a heterozygous, long-finned fish is crossed with a homozygous, short-finned fish. of the offspring, will have long fins and be , and will have short fins and be .

What causes darkening of the skin as melanin production increases