interior & internal
There must exist a difference between them two, or else both of them can't be in the same list to select.

Question

interior &  internal 
There must exist a difference between them two, or else both of them can't be in the same list to select.

Answer

Thank you very much!

Answer

interior = interior of a building, or interior of a building-like organization
opposite of interior = exterior
Generally, the exterior must be visible, the interior is visible only if you go inside.

The body's interior - the body can be considered a building-like structure

Processes are internal or external.

Answer

interior is noun so means....inside.
internal is adjective so means.....of  or  on the inside

Answer

They both have a very similar meaning; however one difference is that interior can be used as a noun or an adjective, but internal can only be used as an adjective.

Example: The building's interior. (The inside of the building - a noun, a thing.)

However internal can only function as an adjective.

The building's internal space is very large. ( here internal (an adjective) describes the space as being internal, not external.)