Combustion and flame — Science STD 8 — Question

List three states in India where earthquakes are more likely to occur.

Name a star having a system of planets with life on one of its planets.

Explain why, the tip of a sewing needle is sharp.

Name the characteristic of sound which depends on:

1. Amplitude.
2. Frequency.

A, B, C and D are the basic part of all the cells. The part A contains threadlike structures called E which transfer the characteristic from parents to their off springs. The part B uses glucose and oxygen to produce energy whereas part C controls the movement of substance into the cell. The part D is a transparent, jelly-like material. What could A, B, C, D and E be?

What are the various practices necessary for raising animals for food and other purposes?

Name the micro-organisms present in the soil and in the root nodules of leguminous plants which can fix atmospheric nitrogen.

What change in the voice of body takes place when they reach puberty? What is the cause of this change?

What is the difference between ‘flora’ and ‘fauna’?

What will happen if personal hygiene (Cleanliness of body) is not maintained by adolescents?