Question

Biological species concepts emphasized on
(a)Geographical isolation
(b)Reproductive isolation
(c)Physiological isolation
(d)None of the above

Answer 1

They are a set of evolutionary mechanisms, behaviors, and physiological processes critical for speciation. They prevent members of various species from producing offspring or make sure that any offspring are sterile.

Complete answer:
A species is a group of organisms with similar characteristics and may interbreed to offer fertile offspring. Speciation is an evolutionary process of the formation of new and distinct species. The species evolve by genetic modification. The new species are reproductively isolated from the previous species. That new species cannot mate with the old species.

Additional Information: Biological species concepts emphasized reproductive isolation. The most common species concept within the biological literature is Mayr's (1970) ‘Biological Species Concept’. The Biological Species Concept defines a species taxon as a gaggle of organisms that will successfully interbreed and produce fertile offspring. According to that idea, a species’ integrity is maintained by interbreeding within a species and by reproductive barriers between organisms in several species. The mechanisms of reproductive isolation have been classified into two broad categories: prezygotic for those that act before fertilization and post-zygotic for those that act after it. The mechanisms are genetically controlled and may appear in species whose geographic distributions overlap or are separate.
So, the correct answer is 'Reproductive isolation'

Note: Due to some geographical changes, few members of a species get isolated from other members. Consecutively, this isolated group develops during a different land and finally evolves as a replacement species with new adaptations consistent with its environment. Natural selection and genetic drift possess a big role to function in this. Allopatric speciation is the sort of speciation caused by geographical isolation, the population being separated through a physical barrier.