The water is flowing towards Town C & D while carrying the harmful substances which was dumped by the factory. Town A & B was not affect as the water was not affected as the direction of the moving water is not upwards.

When decomposition takes place, bacteria releases carbon dioxide

and causes the limewater to become chalky.

(1) cannot be as the water is flowing downstream.

A is located upstream so A is not affected.

(2) cannot be as town water is flowing downstream.

B is located upstream so B is not affected.

(4) cannot be as the water is flowing downstream.

A is located upstream so A is not affected.

(3) is the answer as c is located infront of the factory

and d is downstream of factory as well as c.So d and

c is affected.

The more the GPE the more the KE is being converted.

Flask A is used as control while Flask B ,

which has small pieces of raw meat in it ,

is used to find out if when the pieces of

meat decompose, will carbon dioxide be

given out .

It has greater gravitational force and allows the toy car to travel

further and faster.

Light can't pass through opaque

objects so the cardboard is the one

in the middle.

Option 2 is the only one where the middle circle

is opaque.

Reason: GPE is also converted into KE

The smaller circle in the shadow should be opaque as it is the darkest so it should be cardboard.The bigger circle should be a translucent as it is lighter than the smaller circle but abit dark.The Rectangle should be transparent as it is not dark.

It cannot be B&D as it has high amount of light and the organism is sensitive to light. It has to be A not C as A has high moisture content