A(n) plain is formed where streams deposit fertile soil. a. scroll b. coastal c. glacial d. alluvial

The most appropriate answer is D. alluvial. A glacial plain is formed by the accumulation of till and other debris A coastal plain Would be formed by deposition and erosion from and by ocean waters A scroll plain refers to deposition of sediment from a meandering river, leaving sediment in areas of lower relief I suppose the answer could be a scroll OR an alluvial fan dependent on how specific the question intends to be and the material used to make the question. I would refer to a text to be 100% sure but alluvial is my guess.

Magma is outside the volcano  and lava is inside the volcano. 

Answerwill have thinner; have thicker oceanic sediments;