Coal and Petroleum — Science STD 8 — Question

How can a very heavy machine be moved conveniently from one place to another in a factory? (No crane is available for this purpose).

State three difference between a plant cell and animal cell?

Discuss the effects of deforestation on the following. The next generation.

Hormones play an important role during adolescence.Explain role of hormones in initiating reproductive function in humans, with a flow chart.

What are antibiotics? What precautions must be taken while taking antibiotics?

There is a flu outbreak in your school. Several classmates are absent, while some are still coming to school coughing and sneezing.
1. What immediate actions should the school take to prevent further spread?
2. If your classmate, who shares the bench with you, starts showing symptoms of the flu, how can you respond in a considerate way without being rude or hurtful?
3. How can you protect yourself and others from getting infected in this situation?

If dissolved oxygen of water in lake reduces, what phenomenon it leads to?

Draw a diagram of the Orion constellation to show the position of prominent stars in it.

Name the hormone which would be released during the following situations.
(i) A frightened person
(ii) Growth of a child to adult
(iii) Development of caterpillar to moth
(iv) Development of tadpole to frog

A student staying in a coastal region tests the drinking water and also the sea water 'With a circuit in which a part of the connecting wire is wound around a matchbox containing compass. He finds that the compass needle deflects more in the case of sea water. Can you explain the reason?