ANSWERS

1) c

2) It was the first human-powered airplane.

3) d

4) As a replaceable alternative to space satellites used in relaying voice, television, or Internet signals.

5) d

6) c

7) The male guards the female and their fertilized eggs from rival males.

8) b

9) The more the flyer weighs, the more power it needs to fly. But power sources like batteries only add more weight. So the engineers must design a more efficient wing to generate more lift.

10) Directly underneath the glider, in order to push air up into the wing and generate lift.