Which of the following organisms is likely to have the highest concentration of $D.D.T.$ in its body?

Which of the following does not affect the forest ecosystem?

At the beginning of the twentieth century,forests covered about ....... of the land of India. By the end of the century,it shrunk to.......

Ahmed Khan developed a method to create roads by mixing polyblend and bitumen. The life of the roads constructed in this manner increased by a factor of $................$.

During the past century,the temperature of the Earth has increased by: (in $^{\circ}C$)

$A$ pollutant is an agent which causes change in