Question

concrete is a synthetic material made mostly from rock. concrete can be used to create the outside walls of a building’s basement, as shown below
other materials could also be used for making the basement. some properties of several materials are listed below
concrete

• cracks under stress
• waterproof
• can be poured to make any shape

rock

• hard and strong
• lets water through spaces between rocks
• limited by sizes of available rocks

wood

• can decompose when wet
• absorbs water
• may be eaten by insects

which statement best explains why the outside walls of a basement are most commonly made of concrete instead of the other materials listed?
a. concrete lasts a long time and keeps water out.
b. concrete can change its shape if the ground shifts.
c. concrete is strengthened by contact with water
d. concrete does not use up natural resources.

Explanation:

Basement walls need to resist water and be durable. Concrete’s properties include being waterproof (keeps water out) and synthetic (long-lasting). Rock lets water through, wood decomposes when wet—so concrete’s waterproofness and durability make it ideal. Option A matches these key properties.

Answer:

A. Concrete lasts a long time and keeps water out