Question

How did early humans survive their harsh environments?

a. They built homes out of stone.
b. They built homes out of wood.
c. They built walls around their homes for protection.
d. They lived in caves and rock shelters.

Answer 1

They live in caves and rock shelters

Answer 2

One way in which early humans survived their harsh environments was that "They lived in caves and rock shelters," since these were "natural" barriers that often required little effort to construct.