Question

hannahs invention has made an important contribution to solving the worlds electricity problem. the device uses plastic tubes and a small motor to change water energy into electricity. for people like ruth whose communities struggle with having power all of the time, this device helps a lot. it allows people to keep the lights on, charge batteries, and boil water to make it safe for drinking.
why is the word contribution used to describe hannahs device?
it helps solve a problem.
it is a simple invention.
it is made from plastic.
it uses a small motor.

Explanation:

The text states that Hannah's invention has made an important contribution to solving the world's electricity problem. This indicates that the word "contribution" is used because the device helps solve a problem. The other options (it is a simple invention, it is made from plastic, it uses a small motor) do not relate to the concept of making a contribution to solving a problem.

Answer:

It helps solve a problem.