Directions: Read the passage given below and answer the questions that follow by choosing the correct/most appropriate options: 

Extinction. This ominous word has one meaning. The death of a species. And it is a word that we seem to hear so often these days, especially in the news. But the opposite is possible. Today (July 29), which is Global Tiger Day (also called International Tiger Day), the world and India can celebrate the recovery of at least one endangered species. India is now reporting increased tiger numbers, and a recent International Union for Conservation of Nature assessment suggests that tiger numbers have increased by 40% since 2005. This is cause for celebration. But is the rise in tiger numbers enough to prevent their extinction?

Decades of research in ecology and evolution suggest that numbers are critical to avoid extinction. Populations that are smaller than 100 breeding individuals have a high probability of extinction. At the same time, for populations to persist, they should be part of larger landscapes with other such populations that are connected. Small and isolated populations face a high probability of extinction. This is because small populations are subject to chance/random events. These chance events may cause them to lose advantageous genetic variants, while other, detrimental genetic variants might increase in frequency. This process is called genetic drift. Also, individuals in small populations are more likely to be related, leading to inbreeding. This exposes the many slightly disadvantageous genetic variants that are present in all genomes. When expressed together, these detrimental genetic variants cause inbreeding depression and reduced survival and reproduction of inbred individuals.

A closer look at the distribution of tigers across their range shows that most tiger ‘populations’ are smaller than 100. On their own, most tiger populations do not have a high chance of survival. So why are we not seeing extinctions happening more often? Is this because tiger populations are connected to each other? We know that most tiger reserves in India are small and embedded in human-dominated landscapes. So, does the landscape between tiger reserves (agricultural fields, reserve forests, built-up areas, and roads) allow tigers to move through them?