White tigers are neither a species nor a subspecies, but appear as a result of a recessive trait that rarely occurs in the wild. In the 1950s many zoos deliberately and indiscriminately bred white tigers, but more recently, concerns about the desirability of preserving a trait that presumably hinders tigers' to survive in the wild, and recognition that inbreeding could lead to genetic defects, have caused most zoos to such practices. However, some zoo managers argue that the popularity of white tigers provides income important to the survival of zoo sponsored scientific and conservation programs. They also point out that most of the white tigers captured in the wild were adults, proving that their coloration does not hinder their survival ability.

Opponents of white-tiger breeding programs argue that white tigers are merely Indian tigers—a subspecies well represented in both zoos and the wild—and that zoos should focus their tiger management efforts on preserving subspecies whose existence is threatened, thus preventing the Chinese and Indochinese tiger subspecies from joining the Javan, Balinese, and Caspian subspecies in extinction. Alternatively, zoos could mingle the subspecies and manage all tigers in captivity as one species. Although subspecies differences would be lost, this strategy would be advantageous because fewer animals would be necessary to maintain the genetic diversity of tigers in captivity, making scarce zoo resources available for housing other endangered felines.

Which of the following best describes the function of the last sentence in the first paragraph of the passage (see highlighted text)?

To emphasize the importance of white tigers as source of zoo income

To point out the advantages to white tigers of living in the wild

To provide evidence counter to an argument against the breeding of white tigers

To suggest that white tigers living in the wild are less to face extinction than tigers living in zoos

To suggest that white tigers are not endangered


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