| A | B |
|---|
| photosynthesis | the process by which plants , algae, and some bacteria use sunlight, carbon dioxide, and water to make food |
| atmosphere | a mixture of gases that surrounds a planet, moon, or other celestial body |
| ozone | a gas molecule that is made up of three oxygen atoms |
| orbit | a path that a body follows as it travels around another body in space |
| launch | the process of setting a rocket or spacecraft in motion |
| solar system | the sun and all of the planets and other bodies that travel around it |
| spacecraft | vehicle that is designated to be launched into space to follow a path such as an orbit around Earth or a trip to explore |
| gravity | a force of attraction between objects that is due to their masses |
| weightlessness | the apparent loss of weight of an object that is falling freely in a gravitational field |
