In $Bougainvillea$ and $Cucurbita$,the axillary bud is modified into thorn and tendril respectively. This is an example of:

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$: Forelimbs of humans and bats are homologous.
Reason $R$: Forelimbs of humans and bats have similar anatomical structure.
In the light of the above statements, choose the most appropriate answer from the options given below:

Homologous organs are .......

Which of the following groups in human anatomy consists only of vestigial organs?

Gill clefts and notochord appear in the embryonic development of all vertebrates from fishes to mammals. This supports the theory of

Which one of the following is the correct example of homologous organs?