Biology standard 9

 1. Give examples for plant products having economical importance.

 Coffee, Cocoa, Pepper, Rubber latex, Cardamom

 2 .Chemosynthesis

The process of making energy from chemical compounds by certain organisms with out the help of solar  energy is known as Chemosynthesis.

 eg: Sulphur bacteria can produce energy by oxidising inorganic compound

3. About 70-80% of oxygen in the atmosphere is contributed by ------------ present in ocean ecosystem.

 Algae and phytoplanktons.

4. Who are the chief producers of the ocean ecosystem ?

 Algae and phytoplanktons.

5.Suggest an experiment to prove the release of oxygen molecules during photosynthesis.

 Take a piece of aquatic plant like hydrilla in a glass tumbler, filled with water. Cover the  plant using a transparent funnel. Cover the tail portion of the funnel by a test tube filled with water. Take care to leave a little portion of the tube devoid of water . Keep this device under sunlight for one hour. Observe the air bubbles going upward. 

 The gas is oxygen (released from water molecules during the light phase).

6. Why plants are called as 'the lungs of the earth' ?

 Plants offer great service to the biological world by absorbing CO2 from the atmosphere and releasing oxygen and thus purify the air.

7. Give a few examples for how plants serve in the mitigation of natural disasters

 To some extend, mangrove forests control Tsunami. Plants like bamboo, reed(ദരഭ), vetiver(രാമചം) and lemongrass protect the river banks. Trees and bushes prevent soil erosion and landslide.

8. Make apt slogans for the awareness of reducing global warming.

• Trees – A Solution for Global warming.

• Protect the Green world for a Carbon free world.