| A | B |
|---|
| ancient | very old; from the distant past |
| develop | to bring into being |
| position | the place where something is |
| astronauts | someone trained to travel and work in space |
| astronomy | the scientific study of space |
| vast | very, very large |
| unit | a standard amount by which things are measured |
| surface | the outside part of something |
| orbit | the path one object takes as it moves around another |
| organized | grouped together |
| exist | to be alive or real |
| direct | simple and straightforward |
| intelligence | the ability to learn skills and facts, and to apply them in some way |
| watery | having the quality of water |
| bacteria | a very small life form; germ |
| artificial | made by humans |
| communication | having to do with sending or exchanging information |
| system | a set of things acting together |
| accurate | correct |
