A. mutations are a source of variation in the species B. mutations are the cause of disease in the species
C. mutations are not harmful when they occur in somatic cells of species
D. mutations are always passed on to subsequent generations of the species

it cools slower in the earth meaning the crystals have more time to form than lava on the surface

glacial erosion, the picking up and movement of earth beneath a glacier, is also referred to as plucking. erosion and transportation of individual pieces of bedrock, especially large "joint block occur as a result of this glacial erosion. plucking is type of erosion in which rocks become frozen into the bottom and sides of the glacier.as the glacier moves downhill it 'plucks' the rocks frozen into the glacier from the ground.