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. A concrete foundation poured for the basement of a house. 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
Hard and strong
Rock:

Lets water through spaces between rocks
Limited by sizes of available rocks
Can decompose when wet
Wood:

Absorbs water
May be eaten by insectsWhich statement best explains why the outside walls of a basement are most commonly made of concrete instead of the other materials listed?
a. Concrete is more flexible in shape.
b. Concrete is waterproof and strong.
c. Rocks can decompose when wet.
d. Wood absorbs water and may be eaten by insects.

Answer 1

Concrete is the preferred material for building's basement walls due to its waterproof and strong qualities, making it more suitable than wood or rock, which have limitations against moisture and insect damage.

Step-by-step explanation:

The statement that best explains why the outside walls of a building's basement are most commonly made of concrete instead of the other several materials listed is b. Concrete is waterproof and strong. Concrete's properties make it an ideal material for such structures. It is capable of forming waterproof barriers, which is essential for preventing moisture penetration in basements. Furthermore, concrete's strong nature ensures the structural integrity of the building against various stresses.

Historically, concrete has been used for centuries, where Romans perfected its use by creating a mix that included lime mortar, pebbles, sand, and water, which could be molded into different shapes and hardened to function like stone. In modern times, the advancement of lightweight concrete, consisting of lightweight coarse aggregate with fine aggregates like shale, clay, or slate, has made it even more advantageous for building strong, thermally insulated, and long-lasting structures with lower load requirements and faster construction times.

While rocks can allow water through and may decompose when wet, and wood is susceptible to water absorption and damage by insects, concrete provides durability and resistance to such issues. Hence, concrete is the most suitable material for constructing basement walls due to its strength, waterproof nature, and the flexibility it offers in shaping the structure.