Solution:
Pyramid of number indicates the number of individuals at each trophic level. The pyramid of number is inverted in tree ecosystem. In this, the the first trophic level contains least number of trees. The insects feeding on primary producer occupy second trophic level.

Solution:
Endemic species are plants and animals that exist only in one geographic region. Species can be endemic to large or small areas of the earth: some are endemic to a particular continent, some to part of a continent, and others to a single island.

Solution:
World Wetlands Day is celebrated every year on 2 February to raise global awareness about the value of wetlands for humanity and the planet. It also marks the adoption of the Ramsar Convention on Wetlands in 1971 in the Iranian city of Ramsar.

Solution:
As it travels along the food chain, the concentration of DDT increases.

Solution:
The combination of nitrogen oxides and hydrocarbons in the presence of the sunlight causes smog.

Solution:
Particulate matter consists of soot, flash, dust of various types, fur, hair, spores etc. They are classified into settleable and suspended particulate matter.

Solution:
The areas where soil is washed away into streams, transported into rivers and finally lost to the sea are called ecologically sensitive areas.