Light — Science STD 7 — Question

Write word equations for two chemical reactions with the help of materials given in the box.
(Air, copper sulphate, iron, vinegar, iron oxide, carbon dioxide, iron sulphate, copper, lime water, water)

What is assimilation?

RBCs contains a red coloured pigment which carries oxygen with it. What is the pigment called?

Why does the Pole Star appear fixed in the sky?

Explain the term humus that is generally found in the uppermost layer of soil.

Name some animals living in rainforest.

Mention the common process of cleaning of wastewater.

Name the devices used by our ancestors to measure the time before pendulum clocks.

Name the bacteria that can fix atmospheric nitrogen.

State the name of wind pipe.