Force and pressure. — Science STD 8 — Question

Draw a neat, labelled diagram of nitrogen cycle in nature. Which natural phenomenon occurring in the sky is responsible for nitrogen fixation?

Two very small organisms X and Y both reproduce by the method of budding. Organism X is industrially very important because it is used in making alcohol from sugar. It is also used in making bread. Organisms Y is a tiny animal having tentacles which live in water.

1. What is organisms X?
2. Name the process in which X converts sugar into alcohol.
3. To which class of organism does X belong?
4. What are organisms Y?
5. Out of X and Y, which organism is multicellular and which one is unicellular?

Draw a labelled diagram of larynx and explain its functions.

What is an electroscope? Draw a labelled diagram of an electroscope and explain its working.

Name two places in India where coal is found.

What is air pollution? What are the main sources of air pollution?

What is meant by a non-contact force? Explain with the help of an example.

The substance W is a fossil fuel. It occurs deep below the ground in certain areas of the earth. Another fossil fuel X is found trapped above the deposits of W. When W is subjected to a process called Y, then a number of different products are collected at different temperature ranges which are put to different uses. A special grade of product Z obtained in this way is used as aviation fuel in jet aeroplanes.

1. What are (i) W, and (ii) X ?
2. What is the physical state of (i) W, and (ii) X ?
3. Name the process Y.
4. Name the product Z.

What are metalloids? Name two metalloids.

Where are the following glands located in the human body?

1. Pituitary.
2. Thyroid.
3. Pancreas.
4. Adrenals.