Question

which statement explains one reason why unconformities occur?
rocks along a fault break and move.
igneous rock forms at earth’s surface.
no sediment is deposited over a long time.
igneous rock forms between sedimentary layers.

Explanation:

Unconformities are gaps in the geologic record. When no sediment is deposited for a long - time, it creates a break in the sequence of rock layers, leading to an unconformity. Faulting (rocks along a fault break and move) causes displacement but not necessarily unconformities. Igneous rock forming at Earth's surface or between sedimentary layers doesn't directly explain unconformities as the lack of sediment deposition does.

Answer:

No sediment is deposited over a long time.