Ecosystem

Which one of the following processes during decomposition is correctly described? 

• Fragmentation - Carried out by organisms such as earthworm

• Humification - Leads to the accumulation of a dark coloured substance humus, which undergoes microbial action at a very fast rate

• Catabolism - Last step in the decomposition under fully anaerobic condition

• Catabolism - Last step in the decomposition under fully anaerobic condition

Natural reservoir of phosphorus is 

• sea water

• animal  bones

• rock

• rock

Biotic factors are :

• chemical factors of soil which affect life

• physical factors of soil which affect life

• all living organisms which influence other organisms

• factors of atmosphere which affect life

Match the name of the animal (Column I ) with one characteristic (Column II) and the phylum/class (Column III ) to which it belongs

• 	Column I	Column II	Column III
  a	Petromyzon	Ectoparasite	Cyclostomata

• 	Column I	Column II	Column III
  b	Lchthyophis	Terrestrial	Reptilla

• 	Column I	Column II	Column III
  c	Limulus	Body covered by chitinous exoskeleton	Pisces

• 	Column I	Column II	Column III
  c	Limulus	Body covered by chitinous exoskeleton	Pisces

Secondary productivity is rate of formation of new organic matter by

• producer

• parasite

• consumer

• consumer

During  sewage treatment, biogas are produced, which include

• methane, hydrogen sulphide and carbon dioxide

• methane, oxygen and hydrogen sulphide

• hydrogen sulphide, methane and sulphur dioxide

• hydrogen sulphide, methane and sulphur dioxide

The term ecosystem was coined by

• AG Tansley

• E Haeckel

• E Warrning

• E Warrning

Which of the following would appear as the pioneer organisms on bare rocks?

• Liverworts

• Mosses

• Green algae

• Green algae

During ecological succession

• the gradual and predictable change in species composition occurs in a given area.

• the establishment of a new biotic community is very fast in its primary phase.

• the number and types of animals remain constant.

• the number and types of animals remain constant.

In which of the following both pairs have correct combination?

• Gaseous nutrient cycle	Carbon and Nitrogen
  Sedimentary nutrient cycle	Sulphur and Phosphorus

• Gaseous nutrient cycle	Carbon and Sulphur
  Sedimentary nutrient cycle	Nitrogen and Phosphorus

• Gaseous nutrient cycle	Nitrogen and Sulphur
  Sedimentary nutrient cycle	Carbon and Phosphorus

• Gaseous nutrient cycle	Nitrogen and Sulphur
  Sedimentary nutrient cycle	Carbon and Phosphorus