IMSO 2008 Science Taiwan Second Round Theory I Question 10

Question 10

Section A: choose the correct answer. The supplied key prints 2 points per question and 50 minutes. Source header says Qualifying Examinations; key says Taiwan (2).

Why does Earth’s axial tilt make summer warmer than winter in the Northern Hemisphere?

Warm ocean currents flow from the tropics to the Northern Hemisphere in summer.
Sun rays strike the Northern Hemisphere more directly in summer.
The greenhouse effect increases there in summer.
The Northern Hemisphere is closer to the Sun in summer.