Improvement in Food Resources — Science STD 9 — Question

1. Name the phenomenon which helps fresh water unicellular organisms (e.g. Amoeba) continuously gain water in their bodies. Also, name the mechanisms by which these organisms throw out excess of water from their bodies.
2. Give at least two examples in plants where similar phenomenon in used to gain water.

Explain the methods of, prevention of malaria.

What is the difference between collenchyma and sclerenchyma?

Write down four characteristics of Ctenophora and give two examples.

Briefly describe:

Means of transmission of disease.

Where and how are clouds formed?

Write down the differences between diffusion and osmosis.

Name the fertilizers whose excessive presence in water bodies results in algal growth. What is the consequence of eutrophication.