In evolutionary biology, the convergent evolution is the process by which organisms from different evolutionary lines independently develop similar adaptations or features in response to similar environmental conditions. North American cacti and African euphoria are clear examples of this concept. Both types of plants have developed thick, juicy stems that are ideal for storing water and protecting thorns, and both are well suited to deal with the rain scarcity and dry climate of the desert regions. The two plant species belong to different plant families and are distant relatives in the phylogeny of flowering plants; However, their common characteristics indicate that they are the product of a converging evolution. The convergent development has enabled the two species of plants to develop similar adaptations to facilitate their survival in the hot and dry desert environment in which they live.
The definition of vestigial organs are rudimentary structures in humans
that correspond to a functional structure or organ in an ancestor.
Basically the answer is redundant organs present in an organism, which
have been functional in the organism's ancestors.
