Which one of the following statements is correct for secondary succession?

• It occurs on a deforested site

• It follows primary succession

• It is similar to primary succession except that it has a relatively fast pace

• It is similar to primary succession except that it has a relatively fast pace

Which one of the following statements for pyramid of energy is incorrect, whereas the remaining three are correct?

• It shows energy content of different trophic level organisms

• It is inverted in shape

• It is upright in shape

• It is upright in shape

Of the total incident solar radiation, the proportion of PAR is 

• about 60%

• less than 50%

• more than 80%

• more than 80%

Which one of the following animals may occupy more than one trophic levels in the same ecosystem at the same time?

• Sparrow

• Lion

• Goat

• Goat

Both, hydrarch and xerarch successions lead to

• medium water conditions

• xeric conditions

• highly dry conditions

• highly dry conditions

The breakdown of detritus into smaller particles by earthworm is a process called 

• humification 

• fragmentation

• mineralisation

• mineralisation

Study the four statements (1-4) given below and select the two correct one out of them.

1. A lion eating a deer and a sparrow feeding on grain are ecologically similar in being consumers
2.Predator starfish pisaster helps in maintaining species diversity of some invertebrates
3.Predators ultimately lead to the extinction of prey species
4.Production of chemicals such as nicotine, strychnine by the plants are metabolic disorders

The two correct statements are 

• (2) and (3)

• (3) and (4)

• (1) and (4)

• (1) and (4)

The biomass available for consumption by the herbivores the decomposers is called

• net primary productivity

• secondary productivity

• standing crop

• standing crop

129.

An imporved variety of trasgenic basmati rice

• does not require chemical fertilisers and growth hormones

• gives high yield nd is rich in vitamin-A

• is completely resistant to all insect pests and diseases of paddy

• is completely resistant to all insect pests and diseases of paddy

Which domestic sewage mixes with river water

• small animals like rats will die after drinking river water

• the increased microbial activity releases micronutrients such as iron

• the increased microbial activity uses up dissolved oxygen

• the increased microbial activity uses up dissolved oxygen