HOMOLOGOUS ORGANS -
They are those that have same internal bone structures, but their function differs.
Wing of a bat, the lateral fin of a whale, and the human arm[ they all have similar bone structure layout, but they carry out distinct functions] -- Homologous structures means they had came from a common ancestor.
They are ones that basically have th same function but not the same underlying structure.
Bat 's wing & Fly 's wing- they both are used to help the creature fly, but they have diff patterns in bone structure.
The similarity of the function also reflects that they are adapted to a similar environment!