Keystone species in an ecosystem are those which:
are present in maximum number.
are most frequent.
attain a large biomass.
contribute to ecosystem properties.
In an ecosystem,which one shows one-way passage
Free energy
Carbon
Nitrogen
Potassium
If we completely remove the decomposers from an ecosystem, its functioning will be adversely affected, because:
Energy flow will be blocked.
Herbivores will not receive solar energy.
Mineral movement will be blocked.
Rate of decomposition will be very high.
What is true of ecosystem ?
Primary consumers are least dependent upon producers
Primary consumers out - number producers
Producers are more than primary consumers
Secondary consumers are the largest and most powerful
The major contributor of green - house gases to the atsmosphere is:
Russia
USA
Germany
Brazil
Highest DDT deposition shall occur in
Phytoplankton
Sea gull / birds
Crab
Eel
Phosphate pollution is mainly caused by:
Phosphate rock only.
Agricultural fertilizers only.
Sewage and phosphate rocks.
Sewage and agricultural fertilizers.
Which important green-house gas, other than methane, is being produced from the agricultural fields?
Arsine
Sulphur dioxide
Ammonoa
Nitrous oxide
Pyramid of numbers in a grassland / true ecosystem is
Always inverted
Always upright
Both (a ) and ( b )
Spindle-shaped
Which of the following is the most stable ecosystem ?
Forest
Desert
Mountain
Ocean
