Assertion and Reason 3
11) Assertion (A): The bulb filament is made of silver.
Reason (R): Silver does not melt.
The bulb filaments are not made of silver and silver can be melted.
12) Assertion (A): Telephone wires sag more in summers than winters.
Reason (R): The wires expand due to heat.
The metal of the wires expands in summers due to heat and contracts in winters due to low temperature.
13) Assertion (A): The handles of pressure cooker are made of ebonite.
Reason (R): Ebonite is a hard metal which does not break easily.
The pressure cooker handles are made of ebonite because it is a bad conductor of heat, so the handles do not heat up. Ebonite is not a metal.
14) Assertion (A): The earthworms reduce the fertility of the soil.
Reason (R): They make the soil soft and porous.
The earthworms are good for agriculture. They make soil soft and porous by creating burrows. It allows more water and air to enter in the soil which is good for agriculture.
15) Assertion (A): A fish has a streamlined body.
Reason (R): The streamlined body helps fishes move faster in the water.
It is true that a fish has a streamlined body. A streamlined shape can move faster in water than other shapes.
Assertion and Reason 1
Assertion and Reason 2
Assertion and Reason 4