Answer:
<u>d. Increase of the amount of CO2 in the atmosphere</u>
Explanation:
1) Jupiter is a planet made entirely out if gas, therefore humans can't walk on Jupiter and Jupiter lacks oxygen.
2) Uranus is a Ice giant, that means it's very cold and humans would most likely freeze to death. Also Uranus lacks oxogen..
3) Neptune is the farthest known planet from the sun, that makes Neptune too cold to be lived on.
4)Pluto is far from the sun, which would make it very cold
5) Mars would be perfect for humans, but the o-zone lacks of oxygen. Scientists say, Mars could support like if we simulate life on earth. Mars is also humid enough to support life.
