Answer:
Sarcomere
Explanation:
The sarcomere is the smallest contractile unit of muscle. It extends from one Z disc to the next and therefore, is the region between two consecutive Z discs. It contains an A band flanked by half an I band at each end. Contraction of a muscle fiber occurs as the sarcomeres within the myofibrils shorten. During the shortening of the sarcomere, the thin actin filaments slide past the thick myosin filaments and approach one another. The resultant shortening of the I band and complete disappearance of H zone cause contraction of muscle fiber.
Microscopic hair structures that extend far out from animal cells, they are important and play a vital part in both humans and animals develpoment and everday life..i hope this helps..
2. Ionophores because they are class of proteins that move cell membranes. They are small, hydrophobic molecules that increase a cell's permeability to certain ions.
