Question

this table compares different types of rock.
type of rock\thow does it form?\texamples
igneous\tmelted rock cools and hardens into solid rock\tbasalt, obsidian
sedimentary\tlayers of sediment are pressed together, or compacted, to make rock\tsiltstone, shale
metamorphic\thigh temperature and pressure change a rocks properties\tslate, marble
based on the table, how is siltstone formed?
by the pressing of layers of sediment together\tby the cooling and hardening of melted rock

Explanation:

First, we look at the table. Siltstone is listed as an example of sedimentary rock. The "How does it form?" column for sedimentary rock says "layers of sediment are pressed together, or compacted, to make rock". So we match the formation process of sedimentary rock (which siltstone belongs to) with the given options. The first option "by the pressing of layers of sediment together" matches this description, while the second option describes igneous rock formation.

Answer:

by the pressing of layers of sediment together