A bat's wings may look like sheets of skin. But underneath, a bat has the same five fingers as an orangutan or a human, as well as a wrist connected to the same cluster of wrist bones connected to the same long bones of the ann. What can be more curious than that the hand of a man, formed for grasping, that of a mole for digging, the leg of the horse, the paddle of the porpoise, and the wing of the bat, should all be constructed on the same pattern? Which one of the following is the most logical. Scientific and rational inference that can be made from the above passage?

Correct Option (4)

The passage highlights the fundamental similarity in the skeletal structure of limbs across diverse species such as bats, humans, horses, and porpoises, despite their varied functions (flying, grasping, running, swimming). This shared underlying anatomical pattern, known as homologous structures, is a key piece of evidence in evolutionary biology. Homologous structures indicate that these species descended from a common ancestor, with their limbs subsequently adapting through natural selection to suit different environmental niches and functions over evolutionary time. Therefore, the most logical scientific inference is that these animals share a common evolutionary history.

Incorrect Options:

The passage describes a specific phenomenon within evolutionary biology, not a general concept of biodiversity.

• Option 1: Biodiversity refers to the variety of life forms and ecosystems. While the existence of different species with similar structures contributes to the overall variety of life, the passage's primary focus is on the *reason* for these structural similarities, which points to shared ancestry rather than merely cataloging variety.

• Option 2: The use of limbs for different purposes by various species is an example of adaptive radiation or divergent evolution, where a common ancestral structure adapts to different functions. While this is an aspect of evolution, the core inference from the *similar underlying structure* itself, as emphasized in the passage, is about common ancestry, not just the functional diversity of limbs. This is also not a definition of biodiversity.

• Option 3: Evolutionary processes are driven by natural selection, genetic variation, and common descent, not by random coincidence. The observed structural similarities are a result of shared genetic heritage from a common ancestor, which has been modified over generations, rather than an accidental occurrence.