Which of the following is responsible for the differences in summer and winter temperature stratification of deep temperate zone lakes?

Which of the following is responsible for the differences in summer and winter temperature stratification of deep temperate zone lakes? 

A) Water is densest at 4°C.
B) Oxygen is most abundant in deeper waters.
C) Winter ice sinks in the summer.
D) Stratification is caused by a thermocline.
E) Stratification always follows the fall and spring turnovers.






Answer: A

In temperate lakes, the surface water is replenished with nutrients during turnovers that occur in the

In temperate lakes, the surface water is replenished with nutrients during turnovers that occur in the 

A) autumn and spring.
B) autumn and winter.
C) spring and summer.
D) summer and winter.
E) summer and autumn.






Answer: A

Turnover of water in temperate lakes during the spring and fall is made possible by which of the following?

Turnover of water in temperate lakes during the spring and fall is made possible by which of the following? 

A) warm, less dense water layered at the top
B) cold, more dense water layered at the bottom
C) a distinct thermocline between less dense warm water and cold, dense water
D) the changes in the density of water as seasonal temperatures change
E) currents generated by nektonic animals





Answer: D

Generally speaking, deserts are located in places where air masses are usually

Generally speaking, deserts are located in places where air masses are usually 

A) tropical.
B) humid.
C) rising.
D) descending.
E) expanding.






Answer: D

What is the limiting factor for the growth of trees in the tundra?

What is the limiting factor for the growth of trees in the tundra? 

A) low precipitation
B) cold temperatures
C) insufficient minerals in bedrock
D) pH of soils
E) permafrost





Answer: E

Which series is correctly layered from top to bottom in a tropical rain forest?

Which series is correctly layered from top to bottom in a tropical rain forest? 

A) ground layer, shrub/immature layer, under story, canopy, emergent layer
B) canopy, emergent layer, under story, shrub/immature layer, ground layer
C) canopy, under story, shrub/immature layer, emergent layer, ground layer
D) emergent layer, canopy, under story, shrub/immature layer, ground layer
E) emergent layer, under story, canopy, ground layer, shrub/immature layer





Answer: D

Which of the following investigations would shed the most light on the distribution of organisms in temperate regions that are faced with climate change?

Which of the following investigations would shed the most light on the distribution of organisms in temperate regions that are faced with climate change? 

A) Remove, to the mineral soil, all of the organisms from an experimental plot and monitor the colonization of the area over time in terms of both species diversity and abundance.
B) Look back at the changes that occurred since the Ice Age and how species redistributed as glaciers melted, then make predictions on future distribution in species based on past trends.
C) Compare and contrast the flora and fauna of warm/cold/dry/wet climates to shed light on how they evolved to be suited to their present-day environment.
D) Quantify the impact of man's activities on present-day populations of threatened and endangered species to assess the rate of extirpation and extinction.
E) There is no scientific investigation that can help make predictions on the future distribution of organisms.





Answer: B