Natural Resources — Science STD 9 — Question

Classify the following materials as homogeneous mixtures and heterogeneous mixtures: Soda-water, Wood, Air, Soil, Vinegar, Alcohol and water mixture, Petrol and water mixture, Chalk and water mixture, Sugar and water mixture, Copper sulphate solution.

Name the superclass of Chordata in which lateral line sense organs are found.

Name the leucocytes that increase in number during worm infestations.

What is the difference between ‘distance travelled’ by a body and its ‘displacement’? Explain with the help of a diagram.

In which of the following case do you think the long-term effects on your health are likely to be most unpleasant?

• If you get jaundice,
• If you get lice,
• If you get acne. Why?

A sheet of a paper falls slower than a coin gravity through air. Why?

Arrange the following speeds in increasing order (keeping the least speed first):

1. An athlete running with a speed of 10m/s.
2. A bicycle moving with a speed of 200m/min.
3. A scooter moving with a speed of 30km/h.

Give reasons: A gas exerts pressure on the walls of the container.

Why should preventive measures and biological control methods be preferred for protecting crops?