निम्नलिखित अनुच्छेद पढ़ें और उसके बाद दिए गए प्रश्न का उत्तर दें:
A. स्थानीय आवासों के लिए विशिष्ट प्रजातियों के समूहों का विकास।
B. महासागरों और पर्वत श्रृंखलाओं की उपस्थिति
C. स्थानीय भौतिक और जलवायु परिस्थितियों के लिए विशिष्ट समूहों का मजबूत अनुकूलन
D. इस संदर्भ में ऊपर दिए गए सभी कथन (a), (b) और (c) सही हैं। सही
In English (Question & Model Answer) Invasions of exotic species into new geographical areas sometimes occur naturally without human agency. However, human actions have increased this trickle to a flood. Human caused introductions may occur either accidently or as a consequence of human transport, or intentionally but illegally to serve some private purpose or legitimately to procure some hoped-for public benefit by bringing a pest under control, producing new agricultural products or providing novel recreational opportunities. Many introduced species are assimilated into communities without much obvious effect. However, some have been responsible for dramatic changes to native species and native communities. For example, the accidental introduction of the brown tree snake, Boiga irregularis into Guam, an island in the pacific, has through nest predation reduced 10 endemic forest bird species to the point of extinction.\n\nOne of the major reasons for the world's great biodiversity is the occurrence of centres of endemism so that similar habitats in different parts of the world are occupied by different groups of species that happen it have evolved there. If the species naturally had access to everywhere on the globe, we might expect a relatively small number of successful species to become dominant in each biome. The extent to which this homogenisation can happen naturally is restricted by the limited powers of dispersal of most species in the face of the physical barriers that exist to dispersal. By virtue of the transport opportunities offered by humans, these barriers have been breached by an ever-increasing number of exotic species.\n\nThe effects of introductions have been to convert a hugely diverse range of local community compositions into something much more homogenous.\n\nIt would be wrong, however, to conclude that introducing species to a region will inevitably cause a decline in species richness there. For example, there are numerous species of plants, invertebrates and vertebrates found in continental Europe but absent from the British Isles (many because they have so far failed to recolonize after the last glaciations). Their introduction would be likely to augment British biodiversity. The significant detrimental effect noted above arises where aggressive species provide a novel challenge to endemic biotas ill-equipped to deal with them.
How is homogenization prevented under natural conditions?
A. Evolution of groups of species specific to local habitats.
B. Presence of oceans and mountain ranges
C. Strong adaptation of groups of specific to local physical and climatic conditions
D. All the statements (a), (b) and (c) given above are correct in this context. Correct
Correct Option: (D) All the statements (a), (b) and (c) given above are correct in this context.
The passage mentions all these factors - centers of endemism (local habitats), physical barriers (oceans and mountains), and adaptation to local conditions as preventing natural homogenization.