I just want to check my answers... if you could help?

45.Ocean floor subducts under continents because


A. the ocean floor is made of felsic materials and is heavier than continental material


B. the ocean floor is made of mafic material and is therefore more dense than continental material


C. the ocean floor has a lower density and therefore sinks more easily


D. the weight of the continents is so great tha they push the ocean floor material downward





46.Consider a swamp along the calm backwaters of a river flowing through a flat landscape. Given the nature of this environment; which of the following sediments would be least likely to be deposited there?


A. gravel


B. sand


C. silt


D. clay





47.Karst topography is formed primarily by


A. carbonic acid solution


B. mass wasting process


C. oxidation and hydrolysis


D. exfoliation and hydration





48.A mT airmass is likely to be _______ than a cT air mass because the mT airmass ______.


A. wetter; is warmer than the cT airmass


B. drier; forms under the equatorial low


C. drier; is a cold air mass


D. wetter; forms over the ocean





49.When a cold front approaches, air pressure will initially _____ due to the displacement and uplift of ______ air.


A. decrease; warm


B. increase; warm


C. decrease; cold


D. increase; cold





50.As the discharge of a stream increases, which of the following also happens?


A. Stream channels narrow, become shallower, and lose velocity.


B. The rate of flow decreases.


C. Channel width increases but channel depth decreases.


D. Width, depth, and velocity all increase.


51.Bears eat both plants and animals; therefore they are


A. herbivores


B. carnivores


C. omnivores


D. specialists





52.If you were driving down the highway and saw mountians composed of layered strata, you could be confident that you were looking at


A. a shield volcano


B. extrusive igneous rock


C. batholiths or laccoliths


D. sedimentary rocks





53. On the Earth between 30脗潞 and 60脗潞 north latitude, winds flow from the _______ as they flow out of the _______ pressure zone toward the ________ pressure zone


A. west-southwest; subtropical high; subpolar low


B. west-southwest; sub polar low; subtropical high


C. northeast; subtropical high; subpolar low


D. northeast; subpolar low; subtropical high





54.In order to control flooding, levees are frequently constructed along the banks of rivers to confine flow to the channel. Given this, what happens to the flow velocity and erosive power of the stream during a flood, before the water overflows the levee? (Consider the equation Q=wdv when answering this question.)


A. Velocity increases because the width does not increase, and the erosive power increases.


B. Velocity increases because depth does not increase, and the erosive power increases.


C. Velocity decreases because the depth of the channel is significantly greater, and the erosive power increases.


D. Velocity decreases because the width of the channel is significantly less and the erosive power decreases.





55.What era of the geologic time scale are we currently in?


A. Quaternary


B. Cenozoic


C. Triassic


D. Holocene





56.The reflective quality of a surface is known as its:


A. Albedo


B. Conduction


C. Absorption


D. Scattering





57.Consider a food chain in which a grasshopper east grass, the grasshopper is eaten by a frog, and the frog is eaten by a snake. Given these relationships, which of the following is not correctly matched?


A. grass -- autotroph


B. grasshopper -- herbivore


C. snake -- primary consumer


D. frog -- secondary consumer





58.If the earth did not experience endogenic processes, the landscape would


A. be rugged and of great relief as a result of uplift in the absence of weathering conditions


B. consist of high mountains and hills with smooth, gentle slopes


C. be of very low relief as a result of weathering and erosion in the absence of uplift


D. covered with thick glaciers





59.The construction of a dam across a river is likely to cause ______ upstream of the dam, and _______ downstream.


A. erosion; aggradation


B. erosion; erosion


C. aggradation; erosion


D. aggradation; aggradation|||post your answers and I will tell you which ones are right and wrong.