Select the synonym of the following bold and underlined word in each sentence in the unit

To conserve electricity, we are cutting down on our central heating.

Without plants, most water would run off as soon as it falls, taking away valuable soil.

The loss of much forest is destroying Earth’s plant and animal variety.

Man and most animals need a constant supply of water to live.

In the movie, he plays a concerned and _______ father trying to bring up two teenage children on his own.

If you don't have anything _______ to say, I'd rather you kept quiet.

This is especially worrying when there are about 3,000 plants with values as medicines against cancer, AIDS, heart disease and many other sicknesses.