Explain how human activities can intensify, or even cause a landslide.

Human activities can contribute to several factors which cause landslides. These are mainly due to construction of roads and other building structures which do not have proper grading slopes, poorly planned drainage systems.

These constructions are done by cutting the trees and clearing the vegetation cover which anchors the soil in its place and prevents the rain or the floodwater from causing erosion. When human activities clear such forest areas and vegetation cover away for the requirement of timbers or developmental activities the ground or land remains exposed and is prone to landslides.

individual oxygen atoms are formed during photosynthesis.-c.

i believe it would cause an increase of percipitation, though i could be wrong. so i would say b is the answer.