3. What sedimentary rock is made up of pieces
of shells?
6. EXPLAIN: Why does sedimentary rock form
in layers?
7. EXPLAIN: Why must water evaporate or be
pressed out for sedimentary rock to form?

6. Because of how old the rocks are

Explanation:

6. Sedimentary rock forms in layers because of the order they were formed. The older rocks will form first and as time goes on, rock forms above it to create a new layer, and  so on.

a chair, a bed, and a toothbrush

explanation:

sodium i think the chemical element of atomic number 11, a soft silver-white reactive metal of the alkali metal group.