Question

how the vestigial organs are useful for other

Answer 1

1.degenerated or underdeveloped use less organs of organism are called as vestigial organs.
2.appendix is one of the use less organs in human.
3.appendix which is useless to human,is useful and fully functional organ in ruminants 

(meaning of ruminants is: an even-toed ungulate mammal that chews the regurgitated from its rumen ) 

Answer 2

Answer:

Vestigial organs:

1. Vestigial organs are useless organs that are degenerated or underdeveloped due to non-functionality through several years.
2. Some vestigial organs in humans that are functional in other animals are as follows:

• Appendix: It is fully functional in ruminants for digestion of cellulose.
• Muscles of ear pinna: It is useful in monkeys and other animals like rabbits, cows and horses, etc. for movement of ear pinna.
• Other vestigial organs include the tail-bone, body hairs, wisdom tooth, etc.

Hope you understood mate!!