Some scientists believe that sickle-cell anemia is a beneficial mutation because it:

increases life expectancy
provides immunity to diseases
increases resistance to malaria
adds new information to dna

increases resistance to malaria

Explanation:

Sickle cell anemia is a genetic disorder in which the shape of red blood cells changes from oval to that of sickle. Because of this change in shape, the red blood cells  tend to get stuck in the blood vessels and block them. Apart from this, the life span of sickle shaped red blood cells shortens leading to anemia. But, having sickle cells is advantageous too. Those people who have this disease can never acquire malaria. The parasite known as plasmodium which causes malaria can not infect sickle shaped hemoglobin that is why people having this disease are resistant against malarial infection.

that would be called plucking : )

explanation:

''plucking, also referred to as quarrying, is a glacial phenomenon that is responsible for the erosion and transportation of individual pieces of bedrock, especially large "joint blocks". as a glacier moves down a valley, friction causes the basal ice of the glacier to melt and infiltrate joints (cracks) in the bedrock."