Someone asked this question already and it was answered by @mrsbabyjacob and verified by an expert. Here’s there answer:
“Relaxation occurs when stimulation of the nerve stops. Calcium is then pumped back into the sarcoplasmic reticulum breaking the link between actin and myosin. Actin and myosin returned to their unbound state causing the muscle to relax.”
Another person said they thought the answer was A.
Just don’t want you to accidentally waste your points when there are answers already :)
Chitin, the exoskeleton is composed of a hard chitin.
Ocean Surface Topography. Orbiting spacecrafts make highly accurate measurements of the height of the ocean surface - commonly called 'sea level' - to gather long-term information about the world's ocean and its currents. ... The geoid is the shape the sea surface would have if all the currents and tides stopped.