Hematopoiesis refers to the formation of blood cells within the red marrow cavities of certain bones

True

Explanation:

Hematopoiesis is the production of every types of blood cells as well as blood plasma. Simply put we can define this as the way through which blood cells are manufactured by the body. This process happens in different body organs and tissues like the liver and spleen. In humans, it starts from the yolk sac, to the liver and then bone marrow.

b is dominant over the allele for the white fur.

in 1859, charles darwin set out his theory of evolution by natural selection as an explanation for adaptation and speciation. he defined natural selection as the "principle by which each slight variation [of a trait], if useful, is preserved".