Which of the following has become today’s major cause of mass extinction? adaptive radiation human activities addition of new species

Human activities, because most radiation is contained and in only certain areas is radiation either tested or utilized. human activities, such as forestry, encroach on animals' territories and most of the time because of this loss of resources and space, the animals have a hard time adjusting to new environments and usually are killed.

Its either a) or b),wind and water erosion gradually widen the canyon

Ithink its because more have died recently than in the past.