Question

16. Th e latitudinal diversity gradient refers to what pattem of species diversity? A) For many kinds of organisms, species diversity is greatest near the equator and lowest near the poles. B) For many kinds of organisms, species diversity is greatest near the poles and lowest near the equator C) For many kinds of organisms, species diversity is greatest at low elevation and lowest at high elevation. D) For many kinds of organisms, species diversity is greatest at high elevation and lowest at low elevation E) Plants are most diverse near the equator while animals are most diverse toward the poles. 17. Since atmospheric CO2 levels have been measured the past 50+ years, we have seen increasing amounts in the atmosphere. Why has this happened? A) increasing rates of acrobic respiration associated with the rise in world population B) decreasing rates of oxygenic photosynthesis by plants and algae C) clearing of forests to create agricultural land outside the tropics D) combustion of fossil fuels 18. We are currently at just over 400 ppm CO2 in the atmosphere; in order to not exceed 450 ppm CO, what needs to be done with carbon emissions? A) We must stabilize our current carbon emissions and not exceed the current rate of carbon emissions. B) We must stabilize our current carbon emissions, because our current rate of emissions is equivalent to the net rate of CO2 removal from the atmosphere. C We must decrease our current carbon emissions, because our current rate of emissions exceeds the net rate of CO2 removal from the atmosphere. D) We must decrease our current carbon emissions so that the oceans have time to absorb all the carbon currently in the atmosphere. nisphere, atmospheric CO2 levels are highest in early spring and lowest in early fall. What accounts for this seasonal fluctuation in atmospheric CO. levels? ) Photosynthesis Human activities Respiration Volcanoes hemical Weathering

Answer 1

16. Answer: Option A. For many kinds of organisms, species diversity is greatest near the equator and lowest near the poles

Explanation: Species richness occurs towars the lower latitudes (equator) due to the tropical stable climate, largest biomes, greater sunlight for energy production and less seasonal variation. The given question fits the description of option A. Hence, the correct answer.

17. Option D. Combustion of fossil fuels

Explanation: Combustion of fossil fuels changes the mean state of the climate whereas other factors result in only changes in variability. Atmospheric carbon isotope ratios reveal this burning fossil fuels is the primary source for enormous rise in CO2 levels.

18. Option D. We must decrease our current carbon emissions so that the oceans have time to absorb all the carbon currently in the atmosphere

Explanation: Burning of fossil fuels changes the mean state of the climate whereas other factors result in only changes in variability. Atmospheric carbon isotope ratios reveal this burning fossil fuels is the primary source for enormous rise in CO2 levels. Hence, the reduction of current of carbon emissions can make alleviate the situation and oceans being a sink of atmospheric CO2, can absorb it

19. Option A. Photosynthesis

Explanation: In early fall, photosynthesis in plants is high which makes them utilize CO2 in the atmosphere that reduces the levels of CO2 in atmosphere. But in early spring, the plants conserve their energy and reduce photosynthetic activities which makes the CO2 build up in the ecosystem leading to highest CO2 levels