Ice wedging! Its when it rains into small cracks.. BUT IT FREEZES. Of course water expands when frozen SOOOOO... The icicle forms and expands the hole causing bits of rocks and dirt to be ERODED. Also wind and weather...
Hope I helped :)
In the ocean, it is colder in the deeper parts and warmer in the shallow parts.
You did not offer a multiple choice so we don't know what to choose from.
Africa usually has a hot and humid so cold and/or anything associated to cold is not in Africa.
Both direct material and indirect material