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.
Producing a contraction that changes both the length and the shape of the cell
Answer:
c
Explanation:
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Answer:
Biogeographic isolation affects the changes in gene pools that result from which organisms are breeding -is how biogeographic isolation allows for the change of gene pools over ( time )
Explanation:
The correct answer is that mammals use a closed, double loop , four chambered heart as a circulatory system of the body.
The circulatory system of mammals is closed system that consists of four chambers, two articles and two ventricles. The deoxygenated blood comes into the heart from one loop and the oxygenated blood from other loop from the heart is circulated to the whole body. This is called as double circulation.