The northern hemisphere has a steeper temperature gradient in its winter than the southern hemisphere does in its winter because: a. the earth's axis is tilted 23.5 degrees to the north. b. the northern hemisphere contains more land than does its southern counterpart. c. solar radiation from the sun can vary by as much as seven percent. d. the earth's orbit is not circular.

a. the earth's axis is tilted 23.5 degrees to the north.

Explanation:

The northern hemisphere has 60% of the land as compere to the southern hemisphere and due to the fact that earth rotation on its axis the northern side has extreme temperature gradient in winters due to the tilt is more towards sun and in the southern hemisphere and less in the north thus north has winters and south has summers at the same time ocean has balancing effects on the temperature gradient which are less in northern sides.