Annual variations in the intensity and duration of temperature are due to which of the following factors?

(a) The rotation of earth around the sun

(b) The tilt of Earth's axis around the sun

(c) Humidity that exists due to continuous evaporative effect on the seas

(d) Distance of Pluto from the Earth

Rotation of earth around the Sun and the tilt of its axis cause annual variations in the intensity and duration of temperature, resulting in distinct seasons. These variations together with annual variation in precipitation (remember precipitation includes both rain and snow) account for the formation of major biomes such as desert, rain forest and tundra.