The natural modes of nitrogen fixation are
A) various industrial processes of making fertilizers.
B) fossil fuel combustion.
C) lightning and bacterial fixation in soils.
D) denitrification and various industrial processes.
C
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Humans are protected from air pollution by
a. sneezing and coughing b. mucus capturing small particles c. nasal hairs filtering out large particles d. tiny mucus-coated, hairlike structures called cilia e. all of these answers
Which temperature scale was developed first?
A) Celsius B) Fahrenheit C) Kelvin D) All three were proposed within a year of each other.
Polar regions receive nearly continuous sunlight in the summer months so why doesn't the mean temperature during those months get above 10°C?
A) The reflection of the sun's energy (albedo) by the ice and snow prevents the area from warming. B) The sun's energy has to heat the frozen atmosphere in order to reach the land and that takes all summer. C) In the summer, the winds blow from the cold oceans and keep the temperatures low. D) The sun is too low in the sky to be an effective heat source. E) The ozone layer has thinned significantly over the polar regions and this prevents heat from being trapped near the surface in those areas.
Because of the Coriolis effect, surface ocean currents are deflected to the ________ of their path of motion in the Northern Hemisphere
A) left B) east C) right D) west