Please answer all questions

1		A(n) ______________ is made up of all the populations in a given area.
			A)	biosphere
			B)	community
			C)	habitat
			D)	ecosystem
2		The study of the interactions of organisms with each other and with their physical environment is ____________.
			A)	biology
			B)	science
			C)	ecology
			D)	environmental studies
3		Choose the best definition of succession.
			A)	changes that occur in the physical environment due to geological forces
			B)	factors of the environment determine what species lives where
			C)	progession of different plant species up a mountain slope
			D)	sequential change in the relative dominance of species within a community
4		During the process of primary succession, what stage is likely to occur before the others?
			A)	grasses
			B)	shrubs
			C)	lichens
			D)	climax community
5		The climax community
			A)	is predetermined by the nature of the climate.
			B)	can change as a result of disturbance.
			C)	is always dominated by large trees.
			D)	All of these are correct.
6		The role of an organism within the community is its ___________.
			A)	niche
			B)	habitat
			C)	food chain
			D)	trophic level
7		Consumers that feed on both plants and animals are known as _____________.
			A)	carnivores
			B)	primary consumers
			C)	omnivores
			D)	decomposers
8		Within an ecosystem, green plants can be considered the ______________.
			A)	producers
			B)	autotrophic organisms
			C)	consumers
			D)	Both A and B are correct.
9		The remains of dead animals and plants following their death are called _____________.
			A)	detritus
			B)	decomposers
			C)	soil
			D)	fragments
10		Choose the statement about energy flow and nutrient cycling that is incorrect.
			A)	Only about 55% of food made by producers is available to heterotrophs.
			B)	The laws of thermodynamics support the concept of energy flow through an ecosystem.
			C)	Energy flows through an ecosystem while nutrients cycle.
			D)	Elimination of feces represents nutrients lost from an ecosystem.
11		Complete this grazing food chain: leaves - caterpillars - ____________ - hawks
			A)	grasshoppers
			B)	earthworms
			C)	tree birds
			D)	cattle
12		All the organisms that feed at a particular link in a food chain are called a ____________.
			A)	trophic level
			B)	food web
			C)	pyramid of numbers
			D)	detrital food chain
13		Why do most food chains consist of no more than four or at most five trophic levels?
			A)	Animals mostly graze plants and there are few actual carnivores in nature.
			B)	There is a significant loss of energy at each level.
			C)	It is difficult for ecologists to accurately determine feeding level.
			D)	All of these are correct.
14		Why can some pyramids of biomass be inverted?
			A)	they represent a community that is dying
			B)	after a major disturbance, like a fire, producers are killed
			C)	the producers photosynthesize rapidly and are consumed rapidly
			D)	None of these is correct.
15		Following the rule of 10, eating what trophic level would support the highest human population size?
			A)	first trophic level
			B)	second trophic level
			C)	third trophic level
			D)	fourth trophic level
16		What is not a component of a biogeochemical cycle?
			A)	an exchange pool
			B)	a biotic community
			C)	a reservoir
			D)	None of these is correct.
17		The two general categories of biogeochemical cycles are:
			A)	aquatic and gaseous
			B)	gaseous and sedimentary
			C)	sedimentary and aquatic
			D)	inorganic and organic
18		What main activity or force returns water from land to the sea in the hydrologic cycle?
			A)	precipitation
			B)	transpiration
			C)	gravity
			D)	evaporation
19		Part of the reason that water pollution is such a serious problem is because _________.
			A)	fresh water, used for drinking, makes up only 3% of the world's water supply
			B)	polluted water cannot enter the hydrologic cycle
			C)	plants cannot make use of polluted water
			D)	All of these are correct.
20		The reservoir for carbon in the carbon cycle is _____________.
			A)	the ocean
			B)	the atmosphere
			C)	growing plants
			D)	fossil fuels
21		Global warming, caused by a buildup of greenhouse gases, will likely have what effect in the future?
			A)	greater occurrence of droughts
			B)	reduced agricultural yields
			C)	glacier melt and rising sea levels
			D)	All of these are correct.
22		The action of bacteria is particularly important in the ___________ cycle.
			A)	carbon
			B)	hydrologic
			C)	nitrogen
			D)	phosphorus
23		Bacteria that convert atmospheric nitrogen into a form plants can use are called ___________.
			A)	nitrogen-fixing bacteria
			B)	denitrifing bacteria
			C)	nitrite-producing bacteria
			D)	nitrate-producing bacteria