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

1. It occurs on a deforested site 

2. It follows primary succession

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

4. It begins on a bare rock

Which one of the following statements for pyramid of energy is incorrect, whereas the

remaining three are correct ?

1. It shows energy content of different trophic level organisms

2. It is inverted in shape

3. It is upright in shape

4. Its base is broad

Mass of living matter at a trophic level in an area at any time is called 

1. Detritus

2. Humus

3. Standing state 

4. Standing crop

Of the total incident solar radiation the proportion of PAR is 

1. about 60%

2. less than 50%

3. more than 80%

4. about 70%

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

1. net primary productivity

2. secondary productivity

3. standing crop

4. gross primary productivity

Which one of the following is one of the characteristics of a biological community ?

1. Stratification 

2. Natality 

3. Mortality 

4. Sex-ratio

The correct sequence of plants in a hyrdosere is 

1. Oak→Lantana →Scirpus→Pistia→Hydrilla→Volvax
2. Volvax→Hydrilla→Pistia→Scirpus→Lantana→Oak
3. Pistia→Volvax→Scirpus→Hydrilla→Oak→Lantana
4. Oak →Lantana→Volvax→Hydrilla→Pistia→Scirpus

Which one of the following types of organisms occupy more than one tropic level in a

pond ecosystem?

1. Phytoplankton       

2. Fish

3. Zooplankton         

4. Frog

About 70% of total global carbon is found in

1. grasslands

2. agro-ecosystems

3. oceans

4. forests

The slow rate of decomposition of fallen logs in nature is due to their

1. low moisture content

2. poor nitrogen content

3. anaerobic environment around them

4. low cellulose content