Answer:
Sarcomere
Explanation:
A sarcomere is the basic contractile unit of muscle fiber. Each sarcomere is composed of two main protein filaments—actin and myosin—which are the active structures responsible for muscular contraction.
Answer:
scientific conclusions are reliable as they are helpful for many things however it is true that after the evolution of new ideas the old theory have some changes or may change fully or may be proved wrong but yeah the old theories are still helpful for many reasons and things.
so I think scientific conclusions are reliable