Increase in concentration of a toxicant at successive trophic levels is called

Soil conservation can be best achieved by having

$UV$ radiation from the sun causes which of the following eye disorders?

Choose the correct option regarding the following statements:
$(1)$ $CO_2$ contribution in global warming is $60\%$.
$(2)$ Greenhouse effect occurs due to deforestation.
$(3)$ Due to the greenhouse effect,the present average temperature at the surface of the Earth is $15^oC$.
$(4)$ The amount of $DDT$ in small fish is $0.05\ ppm$.

The monitoring stations,established by $NEERI$,have reported that Kolkata and New Delhi have highest . . . . . . and . . . . . . in air respectively.

Which of the following conferences obtained commitments from different countries for reducing overall greenhouse gas emissions to a level $5\%$ below $1990$ levels by $2008-2012$?