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