Question

5 what is the main idea of this text? a sedimentary rocks are formed over time as layers of sediments become compacted and cemented together. b sedimentary rocks are very different from igneous rocks because they contain fossils and are more easily broken into pieces. c sandstone is a type of sedimentary rock that is formed by small pieces of sand compacted together over a long period of time. d scientists study sedimentary and igneous rocks to learn more about how tiny ocean creatures survive in shallow waters.

Explanation:

To determine the main idea, we analyze each option:

• Option A: Describes the general formation process of sedimentary rocks (layers of sediments compacted and cemented over time), which is a broad and fundamental concept about sedimentary rocks.
• Option B: Compares sedimentary and igneous rocks, but the main idea of a text about sedimentary rocks would likely focus on their own formation or characteristics, not just comparison.
• Option C: Focuses on sandstone (a type of sedimentary rock), which is too specific. The main idea is usually more general about the broader category (sedimentary rocks) rather than one type.
• Option D: Talks about scientists studying rocks to learn about ocean creatures, which is not related to the main idea of sedimentary rocks' nature or formation.

So, Option A best captures the main idea as it explains the core formation process of sedimentary rocks.

Answer:

A. Sedimentary rocks are formed over time as layers of sediments become compacted and cemented together.