The leydig cells secrete :

• oestrogen

• testosterone

• progesterone

• corticosterone

The principal cereal crop of India/Asia is :

• Sorghum

• barley

• wheat

• rice

Removal of top fertile soil by wind or water is :

• Siltation

• Soil erosion

• Weathering of soil

• Leaching

Grassland with scattered trees is :

• savanna

• deciduous forest

• evergreen forest

• tropical rain forest

Two or more species occupying same or ovarlapping areas are :

• sympatric

• sibling

• sub species

• allopatric

Acid rain are produced by:

• excess NO₂ and SO₂ from burning fossil fuels

• excess production of NH₃ by industry and coal gas

• excess release of carbon monoxide by incomplete combustion

• excess formation of CO₂ by coinbustion and animal respiration

In the life scale of mosquito, comma shaped stage is:

• larval stage

• pupal stage

• imago stage

• none of these

A student wants to study metaphasic behaviour of chromosomes in a living cell. The technique most suitable is :

• phase contrast microscope

• x-ray microscope

• cell fractionation

• scanning electron microscope

Outgrowth developing along with hilum of the seed is:

• Plumule

• Radicle

• Strophiole

• Perisperm

Major coffee producing state of India is :

• Tamil Nadu

• Kerala

• Karnataka

• Andhra Pradesh