Genetic mutations introduce new gene forms in a population. For instance, the mutation that affects hemoglobin alters the shape of the red blood cell and makes it sickle-shaped. Which statement
below would explain why the sickle-cell mutation has spread through the gene pool?

A. There is a selective advantage to having Sickle Cell Anemia.

B. This kind of mutation demonstrates a common ancestor.

C. The sickle cell mutation has no benefit.

D. Sickle cell anemia increases the risk of death.

B- this kind of mutation demonstrates a common ancestor.

Explanation:

in order to have sickle cell anemia you need to have both recessive alleles from both parents, this recessive allele has to be continuous passed down from generation to generation on both sides, which shows a common ancestor from long ago

they each offer a fresh glut of resources to the organisms that can arrive and exploit them. as individuals and new species continue to appear, they actively and passively alter the environment. competition for shared resources increases, local abiotic and biotic conditions shift, and the relative abundances of species change accordingly. the process is called ecological succession, and it is one of the earliest and most well-known concepts in ecology.