Question

introduction
a technicians toolbox contains a wide variety of wrenches of all different shapes and sizes; each wrench designed for a specific task or application. most wrenches are made from a steel - alloy called chromium - vanadium (cr - v).
in production, wrenches are heat - treated and chrome - plated after being pressed into the correct shape. this process enhances the properties of the tool; making it less brittle (breakable) and more wear resistant.
2
why are wrenches heat - treated and chrome - plated?
to make them more durable.
to improve grip.
to make them more brittle.
to reduce fragility.

Explanation:

The text states that heat - treating and chrome - plating wrenches makes them less brittle (breakable) and more wear resistant, which means they are more durable and less fragile. There is no mention of improving grip, and making them more brittle is the opposite of what the process does.

Answer:

To make them more durable.
To reduce fragility.