Question

it is cooler in dekalb in the winter because
a the suns rays are more direct in dec/jan.
b the days are shorter and amount of sunlight received is less.
c the northern hemisphere of the earth is tilted towards the sun.
d there is an increase in solar radiation.

Explanation:

In winter, especially in the Northern Hemisphere where Dekalb is likely located, days are shorter and the Earth's tilt means less direct sunlight and thus less solar - energy received, leading to cooler temperatures. Option A is incorrect as sun's rays are less direct in winter in the Northern Hemisphere. Option C is incorrect as the Northern Hemisphere is tilted away from the Sun in winter. Option D is incorrect as there is a decrease in solar radiation in winter.

Answer:

B. the days are shorter and amount of sunlight received is less.