What causes most places on Earth to have seasons?
a) Earth is closer to the Sun in the Northern Hemisphere summer and farther away in the Northern Hemisphere winter.
b) The spin axis is tilted 23.5. degrees to the plane of Earth's orbit, causing solar radiation to vary in angle as Earth revolves around the Sun.
c) The spin axis changes with tilt, causing winter when the tilt is great and summer when the tilt is small.
d) Days are longer during summer than winter, so the extra sunshine causes it to be warmer in summer and less sunshine causes it to be colder in winter.
e) There is more ice in winter, so it is colder, and less in summer, when it is warmer.
Question 2
What is responsible for the red tide phenomenon?
a) The water appears red as a result of reduced levels of photosynthetic pigment.
b) It's a phenomenon that usually coincides with storm surges; the name comes from the red kelp that often washes ashore as a result of rough weather.
c) Red tide occurs in patches of water where certain species of dinoflagellates flourish. They are so abundant that the water becomes discolored and takes on a red hue.
d) Red tides occur once a year and in accordance with the lunar cycle.
(a) Mean duration (days) and (b) average maximum depth (mm) of snow cover throughout northern latitu
Earth and the Moon
Tides on Earth
Layers are deposited parallel to Earth’s surface. Younger layers are deposited on top of older layer
Changes in Earth’s Orbit
Relative Sizes of Dwarf Planets and Earth