For one so plants can produce the oxygen we need to breath
Answer:
2. The altitude of Polaris changes in a definite pattern as an observer's latitude changes.
Explanation:
Since Polaris is located over the Earth’s tilt of axis it appears to follow the observer's latitude. If you were to follow Polaris from the North Pole(0°) to the Equator (90°), it will make a half circle. This will prove that the earth has a spherical shape.
anything of x is base pairs, which can be shown by agct