Improvement in Food Resources — Science STD 9 — Question

Explain, how sonic booms are produced?

Name the complex tissue which helps in:

1. Conduction of water and minerals.
2. Conduction/ transport of food.

1. Squamous epithelium.
2. Columnar epithelium.

What is the reason of increasing concentration of carbon dioxide in the atmosphere?

Give one example of an Indian and foreign poultry breed which when crossed produce an improved variety. List any one desirable trait expected from such cross breeding.

Mention three effects of excessive irrigation