Which physical quantities are to be altered for liquefying gases?

Ravi added a small amount of common salt to water taken in a graduated cylinder. On dissolution,there was no detectable change in the level of water. Explain why this is so.

Which is the correct statement?

$A$ sponge is a solid,yet we are able to compress it. Why?

State whether the following statement is true or false:
$0^{\circ} C = -273 \ K$

$(a)$ Enumerate the changes that take place in a liquid during evaporation.
$(b)$ How is the rate of evaporation affected by changes in the following? Justify your answer.
$(i)$ Temperature
$(ii)$ Wind speed
$(iii)$ Humidity