The crater at Crater Lake was formed by:

A) collapse of overlying rocks into an emptied magma chamber
B) an asteroid impact
C) the erosion of ash and cinders from a circular basin filled with pyroclastics
D) formation of a large sinkhole over a collapsed limestone cavern system

Which of the following is commonly associated with tributaries?

A) rapids when the tributary joins the main river
B) delivery of sediment to the main river
C) an increase in the discharge in the main river
D) all of these

____________________ are plants that grow on other plants and do not have their roots in the soil.

What are some of the advantages of micropower?

What has been an impediment to the development of mass transit systems in North America? 

A)  the expansion of trolley systems 
B)  social stigma about using mass transit 
C)  expensive transit fairs 
D)  a tax system that provides benefits to car drivers

Which of the following controls the rate of groundwater flow?

A) the slope of the water table
B) the permeability of the rocks
C) how fractured the rocks are
D) all of these

Have pesticides been successful in reducing crop losses?

____________________,which involves  planting only drought-resistant species in dry areas,sharply reduces water use on a site.

Microloans are funded by the Grameen Bank in London,England.

A new kitten is added to a home with an established older cat.The older cat hisses and swats at the younger kitten in the kitchen where they are fed.Which term refers to the behaviour of the older cat? 

A)  commensalism 
B)  predation 
C)  mutualism 
D)  competition