a)sponge though compressible is a solid because sponge has many tiny pores inside it which we sometimes used to absorb a liquid or water. this tiny pores inside the sponge creates a hollow space thus making it compressibleb)gases completely fill the vessel in which they are kept because, gases does not have any fixed shape, it retains the size of the vessel in which it is kept,and gas particles always ar in motion

a) A sponge has minute holes in which air is trapped when we press it the air is expelled out and we are able to compress it.

b) This happens because of the fast diffusion of the particles in a gas. The number of vacant spaces or voids in the gaseous state is very large . This means that the particles in a gas move at a very fast speed . they readily fill completely the vessel in which it is kept. This the volume of the gas is same as that of the vessel

(a)A sponge has minute holes in which air is trapped. On applying pressure/ force , the air is expelled out and the sponge gets compressed . On releasing pressure, sponge regains its shape . Thus, sponge is classified as a solid .

(b) In the gaseous state , particles have more kinetic energy and thus particles move freely and have greater space between them.Therefore , particles occupy the entire space available. Hence ,gases completely fill the vessel in which they are kept .