Answer:
B
Explanation:
It's because excessive exercise is going to lower the person's oxygen partial pressure which will cause the affected RBCs to become sickle shaped. When that happens, the cells link to each other and block capillaries that bring oxygen to the tissues and organs. This might result in congestion or ischaemia that damages the tissue.
A is false because iron is required for haemoglobin production so this shouldn't be a problem.
C has no relevance since it won't affect the person's oxygen partial pressure.
D is not going to lower the patient's oxygen partial pressure.
The factor being tested is the variable. There are two types of variables, independent and dependent. The independent variable is the factor being changed by the scientist or the person controlling the experiment. The dependent variable is the thing that gets changed due to the changing of the independent variable. The dependent variable cannot be changed physically by the person doing the experiment.
