Which statement defines the net primary production in an ecosystem over a given time period?
a) the total amount of organic matter in all organisms present
b) the total amount of organic matter in the plants in excess of the used in respiration
c) the total amount of organic matter used in respiration by all the organisms present
d) the total amount of photosynthesis product from all plants
What would be expected to happen if all the nitrogen-fixing organisms ceased to exist?
a) there would be no significant change in numbers of animals
b) the total biomass would be reduced
c) all organisms would die out
d) the nitrogen level of the atmosphere would be increase
Which of the following is NOT recycled in ecosystem?
a) carbon
b) sulphur
c) energy
d) water
The best to increase food production from ecosystem view point is……
a) to increase cultivable land by clearing forest
b) use of excessive fertilizers
c) use of high quality pesticides
d) use of genetically improved varieties of seeds
The total energy from the sun is trapped by the producers in ecosystem is about...
a) 20%
b) 10%
c) 5%
d) 1%
The study of human populations and things that affect them is called…….
a) angiography
b) demography
c) mammography
d) homography
