I think it’s respiratory but I’m not sure
<span>Planets closest approach to the sun is associated with the term perihelion. </span>
Answer:
The correct answer will be option-D.
Explanation:
Calcium plays an important role in muscle contraction as they are released from the sarcoplasmic reticulum after they receive electric impulse.
Calcium triggers the muscle contraction cycle as these calcium ions bind to the troponin-tropomyosin complex. This binding exposes the myosin-binding site on the actin on which high energy myosin binds and cross-bridge is formed.
This cross-bridge formation causes the contraction of the sarcomere and therefore muscle contracts.
Thus, option-D is the correct answer.
The answer is "<span>B: all the gray squirrels that live in a forest" </span>
Photosynthesis<span> is plants taking in water, carbon dioxide, and light to make sugar and oxygen. This is </span>important<span> because all living things need oxygen to survive. All producers make oxygen and sugar for the secondary consumers and then the carnivores eat animals that eat the plants.
Hope this helps</span>
