Atoms and Molecules — Science STD 9 — Question

Write down three basic characteristics of a cell.

“Prevention of disease is more desirable than its treatment”. Justify the statement by discussing three major strategies to be adopted for the prevention of infectious diseases.

1. Name the physical states (i) A (ii) B (iii) C (iv) D, and (v) E.
2. Name one substance belonging to state C which can directly change into vapours on heating. What is this process known as?
3. Name one substance which normally belongs to state B but whose solid form changes directly into gaseous state.
4. Name the most common substance belonging to state A.
5. Which state of matter makes the sum and other stars to glow.

What is water cycle? Give its other name.

The production of food from animal sources has increased greatly in the last few decades. Justify it.

State and explain in brief the four major factors, which are causes of disease.