The degenerated and non functional organs of animals are called _______ organs.
The organs P and Q of two animals have different structures but similar functions. On the other hand, the two organs R and S of two other animals have the same basic structure but different functions. (a) What are the organs like P and Q known as (b) Name the organs like P and Q. Also name the animals which have such organs. (c) What are the organs like R and S called? (d) Name the organs like R and S. Also name the animals which have such organs.