Answer:
<h2>A</h2>
Explanation:
Pepsinogen is an inactive enzyme which is activated into active digestive enzyme known as pepsin. It is a digestive enzyme which causes breakdown of proteins. Active pepsin causes cleavage of more pepsinogen molecule by a positive feedback loop and leads to increase in the concentration of active pepsin molecule.
Its concentration increases according the requirement in the body which is controlled by feedback system.
<span>Answer:
Respiration is a very important process that happens in all living things. It is the way in which our bodies release energy from the food we eat.
When your hand is above your head, the flow of blood is reduced. This means the
supply of glucose and oxygen to the cells is limited, they respire less, and release less
energy. Therefore, the cells get tired more quickly and ache more readily. Pupils may
also account for their results by discussing anaerobic respiration.</span>
Transport carrier proteins.