Answer:
Answers are explained below...
Explanation:
1. A muscle fiber is composed up of myofibrils that contain an arrangement of sarcomeres (A sarcomere is the basic contractile unit of a myofibril...)
Moreover a sarcomere also contains actin and myosin filaments for relaxation and contraction of a muscle as a whole.
2. The motor unit of a muscle is composed up of a neuron called as motor neuron (you can guess by it's name that it serves some motor function). The axonal endings of a motor neuron are embeded in a muscular fiber. A series of nerve impulses control the action of muscle.
Sorry because of time limit...
The Cretaceous Period was the last and longest period of the Mesozoic Era. It lasted 79 million years.
I believe its C because it seems the most reasonable.
It's need to pass oxygen to the blood to the respiratory system work properly I think that the answer
The answer is b. ectomorphs because they have bodies that are tall and thin <span />