Which gas is called dry ice? Why?

Define the following terms: $(i)$ Rigidity,$(ii)$ Compressibility,and $(iii)$ Density. Compare any two states of matter on the basis of the above-defined properties.

$(a)$ State one similarity and one difference between evaporation and boiling.
$(b)$ Account for the following:
$(i)$ We wear cotton clothes in summer.
$(ii)$ $A$ wet handkerchief is placed on the forehead of a person suffering from high fever.
$(iii)$ Wet clothes dry slowly during the rainy season.

Define the melting point of a solid. At what temperature in the Kelvin scale does ice melt? In the experiment to determine the melting point of ice,why does the temperature not rise until all the ice melts,even though heat is continuously supplied? What is this heat energy called?

Why does perspiration keep our body cool?

Convert $300 \ K$ into Celsius scale and $-10^{\circ}C$ into Kelvin scale.