If you live in earth's northern hemisphere, on june 20th or 21st you experience summer solstice, which represents the official start of summer. this is the longest day of the year. what causes this change in day length?
a) the apparent counterclockwise movement of the earth.
b) the earth is orbiting closest to the sun at this time.
c) earth's tilt toward the sun is maximized at this time in the northern hemisphere.
d) the northern hemisphere is tilted toward the sun while the earth is orbiting at its closest point to the sun.