Answer:
The environment that it lives in has not changed much, therefor there is no need for evolution to take place.
Explanation:
Leukopenia means a low count of white blood cells in the body. When there is a low white blood cell count in the body, and in particular a low level of neutrophils (a kind of white blood cell that fights infection), there is quite a significant risk of developing an infection, and once an infection is developed and the white blood cell count is low, the body will not be able to protect itself and fight off the infection. In severe cases , infection may lead to death.
The answer would be hypothalamus.
Hypothalamus is a part of the brain that located below the thalamus (hypo mean "under"). Hypothalamus can control nervous and endocrine system. It was divided into front/anterior, tuberal and back/posterior part. Thirst would be regulated by anterior and posterior part, temperature by anterior part and sexual behaviour by anterior part.
In oxidation, oxygen is needed to create a chemical reaction.