The Fundamental Unit of Life — Science STD 9 — Question

Why does a gunman get a jerk on firing a bullet?

Write down four main characters of Pteriodophyta. Give two examples.

Name any two environmental problems caused by the various activities of human beings.

Name respiratory diseases that may occur due to air pollution.

If a balloon filled with air and its mouth untied, is released with its mouth in the downward direction, it moves upwards. Why?

State which of the following situations are possible and give an example for each of these.
(a) An object moving with a constant acceleration but with zero velocity
(b) An object moving in a certain direction with an acceleration in the perpendicular direction.

Name the tissue found between the organs. What is its function?

Non metals are usually poor conductors of heat and electricity. They are non-lustrous, non-sonorous, non-malleable and are coloured.

1. Name a lustrous non-metal.
2. Name a non-metal which exists as a liquid at room temperature.
3. The allotropic form of a non-metal is a good conductor of electricity. Name the allotrope.
4. Name a non-metal which is known to form the largest number of compounds.
5. Name a non-metal other than carbon which shows allotropy.
6. Name a non-metal which is required for combustion.