The basic structure of a muscle fiber is comprised of actin and myosin protein chains that straddle each other in a fusiform arrangement. The actin and myosin arrays interlock and move past each other to cause contraction of the muscle. They then move back to their initial positions in relaxation. This gives muscles their elasticity and distensibility. The muscle fibers are bundled, in their 10s to 100s up into myofibrils around an endomysium. Many myofibrils are also bound up in a perimysium to form a muscle fiber.
Well, there's producers and consumers. There is also one provider that is the main source of energy for all living things which is the sun. The sun provides sunlight for the producers to make their own food through photosynthesis then consumers come and eat the producers(plants) and that gives them energy. And then predators come and eat that animal and that provides their energy.
<span>I believe the answer is: D. proteins
The main functions of these proteins is to allow specific substance to pass through the membrane of the cells which needed for the energy formation for cells'functions.It created through the combination of more than 20 amino acids with different functions.</span><span />
I think it would be D. because your hypothesis wasn't correct.
