Answer:
The reason is because the heart requires more oxygen when exercising. Several physiological events happen to increase the blood flow and therefore oxygen flow to that muscles,including the heart.
Also the volume of blood that the heart pumps out is maintained so that the body organs receive the necessary amount of oxygen and nutrition, because if it didn't adjust the flow of blood to match activity level, you will be insufficient. Either output method will be lower than needed.
Answer:
B. Modifying the rules
Explanation:
The answer is not A because there's no rule that the team must be rotated.
As for increasing or decreasing the difficulty, it is really subjective to the point of view of each team.
Therefore, the answer is "modifying the rules".
Dichotomous Key is an important tool in determining the identity of an organism and other objects in nature. Hopefully I helped :) Give me 5 stars and brainiest!!