Answer:
As I think second option is the correct one.
Explanation:
The myofibrils are made up of thick and thin myofilaments, which help give the muscle its striped appearance. The thick filaments are composed of myosin, and the thin filaments are predominantly actin, along with two other muscle proteins, tropomyosin and troponin.
Answer:
a. sister chromatids
b. histone
c. metaphase plate
d. interphase (if not a choice, then prophase)
B) Viens
The veins have valves to keep the blood pumping out and not coming back in the heart.