Which of the following is the main by-product of photosynthesis.

Which of the following is the ecological sense that the totality of the physical and chemical factors that constitute the general environment.

Which of the following is included in biosphere 

Marine eco-system includes the oceans, estuaries and 

Which of the following element  is very significant in the environment.

Which of the following is disturbed due to natural hazards, human interference and introduction of exotic species.

The study of the earth as a household, of plants, human beings, animals and micro-organisms is called

 How many major biomes are there in the world.

Which of the following food chain starts with a plant.

A system consisting of biotic and abiotic component is known as