Some Natural Phenomena — Science STD 8 — Question

Explain the importance of reproduction in organisms.

What is the difference between the burning of a candle and the burning of a fuel like coal?

Write True and False against the following statements and also correct the false statement. A physical process in which a substance reacts with oxygen to give off heat is called combustion.

Which synthetic fibre feels like wool and used as a substitute for wool?

Fill in the blanks. Blue green algae fix _________ directly from air and enhance fertility of soil.

Which of the following can be beaten into thin sheets?

Pick out the odd one from the following words given in the box and give reason for it .
Plough, Seed drill, Hoe, Chain pump, Sickle

If scientists know so much about earthquakes, can they also predict when and where next one will strike?

Which part of a plant cell protects outside of the cell?