Unfortunately, they didn’t ______ anything new while doing the experiment.

• use up

• come across

Today in class we looked at ______ images of the Earth.

• species

• satellite

Part of the sun’s energy is absorbed by the Earth’s ______ .

• atmosphere

• investigation

The _______ of Mars is covered with rocks.

• atmosphere

• surface

Biologists are now ______ the plants and animals in this part of the ocean.

• launching

• observing

It’s better to take a backpack __________________ a suitcase when you are traveling to different places.

Is there another room available? I’d prefer a mountain view ________ an ocean view.

She prefers sitting at the back of the class ______ sitting at the front.

It’s quicker to travel by plane ______ train.

There is _______ oxygen in the air in higher places.