Gunpreet, Subject Matter Expert at Edumarz
Answer: The correct option is (d) – all of the above
Homologous organs are those organs that have the same origin and structure but different functions. Because their origin is the same, this shows that organisms with homologous organs have inherited their characters from common ancestors.
(a) Our arm and a dog’s fore-leg: Human beings’ arms and a dog’s fore-leg both have different functions but their structure is the same, which means they share a common ancestry.
(b) Our teeth and an elephant’s tusks: These are also homologous structures because their structure is the same (both are incisors), however, human beings’ teeth are used to chew food while elephant‘s tusks are used to hold objects and dig for food.
Human incisor Elephant tusk
(c) Potato and runners of grass: Potato tuber and runner of grass are homologous structures because they both are stem but serve different functions.
Potato tuber Runner of grass