Which best describes the general air temperature on a cloudy night

The correct answer would be "higher as compared to the clearer night".

On cloudy nights, most of the infrared radiations or heat energy radiated from the surface of the earth are absorbed or trapped by clouds and are re-emitted from the clouds due to which the temperature of the air becomes higher.

In contrast, on clear nights due to the absence of clouds, most of the radiations escape into space due to which the temperature of the air is comparatively cooler or lower.

i do not know and i have a 100 in this class

not necessarily. higher fitness requires the organism to be reproductive successful. for example, an organism at age 10 with 15 offspring is much more fit than an organism at age 15 with only 5 offspring.