Her work has been _______ to the project's success.

• exceptional

• worldwide

• crucial

These lights don't ______ much electricity.

• shrink

• consume

• focus on

The machine _____ a high-pitched sound when you press the button.

• emits

• investigates

• vanishes

America has played a ______ role in the peace process.

• renewable

• major

• urgent

There are laws ______ advertising.

• investing

• generating

• regulating

Our hopes suddenly ______.

• vanished

• converted

• cut down on

Solar panels _____ the heat of the sun into energy that can be used to power homes

• release

• use up

• convert

How long will it be before the world's fuel supplies are ______?

• reversed

• exhausted

• encouraged

This book is the result of _______ research.

• meticulous

• limited

• sustainable

______-cutting down of trees- has several negative effects on the nature.

• reducing

• motivating

• logging