Name the pioneer species that invade in primary succession on bare rock and in water.

(a) Differentiate between active and passive immunity.

(b) Comment on the role of vaccination and immunization in keeping human population healthy.

OR

Describe the process of secondary treatment given to municipal waste water (sewage) before it can be released into fresh waterbodies. Mention another benefit provided by this process.

A plastic sack manufacturer in Bengaluru, Ahmed Khan has managed to find an ideal solution to the problem of plastic waste. Explain in five steps the efforts of Ahmed Khan to meet the challenges of solid waste management.

OR

(a) What does an ecological pyramid represent? State any two limitations that these pyramids have.

(b) Describe an inverted pyramid of biomass with the help of an example.

‘‘For a common man both mango and strawberry are fruits, but not for a biology student. Justify.

Explain the process of gel-electrophoresis technique.