Answer:
Red Blood Cell lacks a nucleus, it would be unable to carry oxygen efficiently.
Explanation:
The absence of a nucleus is an adaptation of the red blood cell for its role. This allows the red blood cell to contain more hemoglobin and, therefore, carry more oxygen molecules. It also allows the cell to have its own distinctive bivalve shape, which promotes diffusion.
False, that is one thing many people were always doing, back then.
it regulates blood sugar level.
Explanation:
Insulin helps control blood glucose ( sugar) levels by signaling the liver and muscle and fat cells to take in glucose ( sugar) from the blood. Insulin therefore helps cells to take in glucose (sugar) to be used for energy. If the body has sufficient energy, insulin signals the liver to take up glucose ( sugar) and store it as glycogen.