<span>When there is no oxygen, or the organism cannot use oxygen for respiration.
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b. the first stage because it could never be in the secound stage
Answer:
Option A, by having a constant supply of blood
Explanation:
Blood that flows to the muscles bring oxygen from the atmosphere to the contracting muscles where it gets consumed. During large muscle exercise, two physiological needs arise – a) high and prolonged muscle blood flow and b) regulation of blood pressure so that there is adequate perfusion of pressure to all organs. In order to meet both the requirements, the blood flow increases so that the vasoligating muscles do not outstrip the cardiac output.
Hence, option A is correct
Answer: Helps the plant breathe: The epidermis of the leaf contains guard cells that control and regulate the small pores on the undersurface of the leaves. These pores are called stomata. Stomata are responsible for regulating water in and out of the cell. It is also responsible for the exchange of gases across the epidermis.
