Answer:
The amount of people per square mile or kilometer of land; also called arithmetic density.
Answer:
many moons
Explanation:
None of Jupiter's moons have more than traces of atmosphere, so their skies are very nearly black. ... For an observer on Io, the closest large moon to the planet, Jupiter's apparent diameter would be about 20° (38 times the visible diameter of the Moon, covering 5% of Io's sky).
The two categories would be Biotic and Abiotic
