What are the characteristics of a sound ? Discuss each one of them briefly.

a) What is an age-pyramid? b) Name three representative kinds of age-pyramids for human population and list the characteristics for each one of them.

a) What is an age-pyramid? b) Name three representative kinds of age-pyramids for human population and list the characteristics for each one of them.

a) What is an age-pyramid? b) Name three representative kinds of age-pyramids for human population and list the characteristics for each one of them.

What is sound ? Discuss the method of its production.

Briefly give the characteristic of monocotyledonous plants.

What is sound ? List its characteristics

Briefly describe about characteristics of Population.