What term describes something that is taken up inside, similar to a sponge?

The term that describes something that is taken up inside, akin to the way a sponge soaks up water, is "absorbed." Absorption refers to the process where one substance is taken into the interior of another substance. In this case, a sponge absorbs water by allowing the liquid to enter and fill its porous structure, ultimately becoming part of the sponge.

This process is different from adsorption, which involves the adhesion of molecules from a gas, liquid, or dissolved solid to a surface. Adsorption is more about the "stickiness" of one substance to another rather than being pulled into its interior.

Elimination refers to the process of removing waste or unwanted materials from a system, which is not applicable to the scenario of being taken up inside. Extraction typically involves removing a substance from a mixture or environment rather than the uptake of a substance into another.

Thus, absorption is the correct term when describing the internal taking up of a substance, similar to a sponge’s function.