Primary succession a) is caused solely by human events. b) occurs on preexisting soil. c) occurs in areas without soil. d) becomes normalized by climate species.

C) Occurs in areas without soil.
Primary succession occurs in lifeless areas in which soil that is incapable of sustaining life is formed due to lava, sand dunes, and rocks left from a retreating glacier.

Nimbostratus is the correct answer.
explanation: nimbostratus clouds are the type of clouds that are mostly likely present on gray, rainy day. these clouds produce continuous rain, snow and there is no thundering or lightening either.

Tta ttc ctg i hope its right.