All cells have a cell membrane. its basically what protects the cells from getting toxins that are sometimes entering your body. without a membrane on all cells, you would get sick a lot!!
Cellular Respiration is the making of energy in the mitochondria. Photosynthesis is the production of oxygen in the chloroplasts. Their reactants are the products of each other.
Answer:
isometric contraction
Explanation:
An isometric contraction occurs as the muscle produces tension without changing the angle of a skeletal joint. Isometric contractions involve sarcomere shortening and increasing muscle tension, but do not move a load, as the force produced cannot overcome the resistance provided by the load.
Excitation-contraction coupling refers to the series of events that begins with the excitation of the sarcolemma in response to stimulation by a neurotransmitter, and results in the release of calcium ions from the sarcoplasmic reticulum.
Hence, option D is the 1st process that starts the excitation-contraction coupling.
