The answer is “The Nervous System”
Answer:
sarcoplasmic reticulum deteriorates and ATP production is stopped
Explanation:
Rigor mortis is the third stage of death characterized by stiffening of joints and muscles in body. The stiffening occurs because muscles are not able to return to the relaxed state. There are two reasons for rigor mortis, depletion of ATP and increase in calcium concentration in cytosol. Due to these factors the actin-myosin crossbridge is not able to break and the muscles remain in contracted state.
Sarcoplasmic reticulum deteriorates and calcium is released into the cytosol. Sarcolemma ( covering of muscle fiber ) also breaks down releasing extra calcium into the cytosol. Calcium is responsible for formation of actin-myosin cross bridge and when its concentration increases the bridge is formed continuously leading to stiffening of muscles and joints.
Whales have horizontally positioned tales opposed to fish and they swim in an up and down type of motion to move, where as fish are the exact opposite flexing and turning their body left and right with their vertical tale to move.
Whales have bigger mouths to eat large schools of krill (their main source of food)
And also, whales are mammals, and breathe with their lungs, whereas fish use gills to breathe underwater. I hope this helped! Please mark Brainliest!