Humans evolved 3 billion years ago after the earth was formed.<span />
Switch A and D, but other than that your answers are correct.
An astronomical body is an object in space.
A comet is a celestial object consisting of a nucleus of ice and a stream of gas and dust.
A moon is an astronomical body that orbits around a planet.
A galaxy is a system of start held by gravitational attraction.
The correct answer is <u /><em>a</em><em>daption</em>. The particular environment in which a particular environment is exposed to gives it the characteristic or the ability to adapt. This is how a particular ecosystem works. It is the relationship of organisms within their environment that evolves through time in order for it to survive and propagate into more adapted kinds of species.
Happy to help!
