Microorganisms: Friend and Foe — Science STD 8 — Question

On a cold winter night, the persons sleeping in a room with closed door and windows with a coal fire burning inside may die due to the excessive accumulation of:

A big wooden box is being pushed on the ground from east to west direction. The force of friction due to ground will act on this box towards:

Name the process in which tadpoles develop into the young frogs.

Large amplitude of sound vibrations will produce:

Which of the following statements is not true for organic manure ?

Rocket has a special streamlined body in order to:

Assertion (A): The removal of frogs from a food chain can increase the grasshopper population.
Reason (R): Frogs are natural predators of grasshoppers.

Which of the following is usually referred to as ‘black gold’?

To an astronaut, the outer space appears:

The synthetic fibre a is chemically a polyamide whereas the synthetic fibre b contains a large number of easter groups. Another synthetic fibres c is made of a polymer d the which consists of a large number of glucose units joined one after the other. Which fibre is prepared from the natural raw material?