Donna is measuring rainfall over a large elevation gradient in the Cascade Mountains of Oregon. As she walks up the west side, she notices that rainfall increases and that when she reaches the top and walks down the east side, it is much drier. This is because:
a. dry air from the equator flows east at this latitude, dropping moisture on the west side.
b. wet air from the tropical equator flows east at this latitude, dropping moisture on the west, and then becomes dry by the time it reaches the eastern side.
c. air is flowing from the west and drops moisture as it rises and cools, then absorbs moisture from the land as it descends and warms.
d. warm air from 30° latitudes picks up moisture as it travels to 60° north, then drops this moisture as it cools.
e. the rain-shadow effect means that cool, moist air drops rainfall as it warms with a rise in elevation.
A lake affected by high levels of artificial eutrophication will have:
a. high nutrient levels, large phytoplankton populations, and low oxygen levels at depth.
b. high level, nutrients, low phytoplankton levels, and high oxygen levels in surface waters.
c. low nutrient levels, large phytoplankton populations, and low oxygen levels at depth.
d. low nutrient levels, low phytoplankton populations, and high oxygen levels at depth.
e. low nutrient levels, large zooplankton populations, and low phytoplankton levels.