The advantage/s of fire:

A. Reduction of biotic thrust
B. Destruction of diseased plants
C. Both (a) & (b)
D. None of these

A0 layer of soil contains

A. Mineral soil
B. Litter
C. Unweathered material like rock
D. None of the above

The orange and red wave lengths of light are able to penetrates in a sea upto a depth of:

A. 5 meters only
B. 20 meters only
C. 50 meters
D. 80-100 meters

Plants growing on rocks are called on:

A. Psychrophytes
B. Lithophytes
C. Halophytes
D. Sciophytes

The plants present on the sand and gravel:

A. Lithophytes
B. Oxalophytes
C. Phancrophytes
D. Psammophytes

Deserts plants have longer root system because:

A. High temperature of soil encourages root growth
B. Low temperature at night encourages root growth
C. Those plants adapted to produce long system can survive better in desert
D. Roots grow in search of water

A population of individuals of a species which are interfertile but differ genetically is called:

A. Ecad
B. Ecotone
C. Ecotype
D. Biome

Soils having sub-optimum concentration of nutrient solution are called:

A. Hypotrophic
B. Eutrophic
C. Heterotrophic
D. Oligotrophic

The water held tightly in a thin film by te soil particles is known as:

A. Run away water
B. Hygroscopic water
C. Capillary water
D. Gravitational water

In which of the following groups, all the plants belong to the same category?

A. Nymphaea, Poamogeton, Victoria
B. Utricularia, Typha, Aponogeton
C. Lemna, Spirodela, Azolla
D. Ranunculus, Vallisneria, Hydrilla