How do Organisms Reproduce? — Science STD 10 — Question

Things always look small on viewing through a lens. What is the nature of the lens?

Name the plant hormones which are responsible for the following effects:
Bending of stem towards light.

Name the structural and functional unit of nervous system.

Name any three forms of energy which could be harnessed from the sea.

Explain why plaster of Paris should be stored in a moisture-proof container.

Arrange the following fuels in the order of increasing calorific values (keeping the fuel with lowest calorific value first):
LPG, Coal, Alcohol, Dung cakes, Diesel

Identify the type of chemical reaction taking place in the following:
On heating copper powder in the air in a china dish, the surface of copper powder turns black.

Which type of lenses are:

1. Thinner in the middle than at the edges?
2. Thicker in the middle than at the edges?

Give one example of a combination reaction which is also endothermic.