Northern hemisphere winters are colder than northern hemisphere summers because
a. Earth is closer to the Sun during the summer than it is during the winter.
b. the snow that falls in the northern latitudes cools Earth during the winter.
c. the light from the Sun shines more directly on the northern hemisphere during the summer.
d. the period of sunlight is longer during the summer than during the winter.
e. the light from the Sun shines more directly on the northern hemisphere during the summer and the period of sunlight is longer during the summer than during the winter.
Question 2
Relative to the stars in the sky, the Sun moves
a. about one degree westward each day.
b. about one degree eastward each day.
c. about 360 degrees westward each day.
d. about 360 degrees eastward each day.
e. along the celestial equator.
Annual net primary productivity on Earth.
Northern Chinese leopard kept in the Jardin des Plantes, Paris
Possible Earth 5 billion years from now
Northern ice cap of Mars in 1999
Earth as a System: The Hydrologic Cycle
Precession of Earth