They act as barriers to sound pollution and also act as dust catchers.

Yes; fertilizers in water body can lower the DO of water body to zero.

It produces vehicles which can run on dual mode like petrol and CNG. This technology reduces consumption of fossil fuels and produces less environmental pollutants.

Nuclear fall out refers to settling down of radioactive particles from the air on to the land. From the soil, these are absorbed by plants, whence they reach the animals and humans via food chains.

The quantitative pollutants are materials that are normally present in the environment but are also added in large amounts by man, e.g., CO₂.

With increase in human population and industrialisation, the waste materials multiplied in amount as well as in kind, and these polluted the environment.

When a species becomes extinct, the plant and animal species associated with it, in an obligatory way, also become extinct, its parasites also vanish. This is called co-extinction.
Some other examples of co-extinction are; plant-pollinator mutualism where extinction of one leads to the extinction of one leads to the extinction of other. Monophagous insect that feeds on particular plant species becomes extinct due to extinction of that plant species.

One can go to place like sea shore in tropical region as Kerala.

Sacred Groves are the tracts of forests where all the trees and wildlife within were venerated and given total protection.
(i) These are the last refuges for a large number of rare and threatened plants.

The two major causes other than anthropogenic causes of the loss of biodiversity are
(i) Alien species invasions When alien species are introduced unintentionally or deliberately in a habitat, some of them can cause decline or extinction of indigenous species.
(ii) Co-extinctions when a species becomes extinct, the plant and animal species associated with it, in an obligatory way, also become extinct.