What is the overall tone of the passage? (A) heavy and defensive (B) serious and informative (C) personal and reflective (D) assertive and persuasive

A. Established in 1910 and built on 90 acres, the St. Louis Zoo is in many ways archetypal of institutions struggling to adapt from a late-19th-century concept to a 21st-century crisis management center. In their first century, American zoos plucked exotic animals from the wild and exploited them mainly for entertainment value, throwing in some wildlife education and a touch of preservation. When wilderness began disappearing, causing animals to fail at an accelerating pace, zoo officials became rescuers and protectors. Since the 1980s, zoos have developed coordinated breeding programs that have brought dozens of animals, like the golden lion tamarin of Brazil, back from the brink. To conserve animals effectively, however, zoo officials must winnow species in their care and devote more resources to a chosen few. The result is that zookeepers, usually animal lovers to the core, are increasingly being pressed into making cold calculations about which animals are the most crucial to save. Sometimes, the burden feels less like Noah building an ark and more like Schindler making a list. All sorts of criteria are considered, including uniqueness, level of endangerment in the wild, importance of the animal’s ecological role, and whether there is an adequate population in captivity for effective breeding. 9 Zoos are essentially given a menu of endangered species that the Association of Zoos & Aquariums is trying to maintain and can then choose according to their particular needs. But final decisions are often as much about heart as logic. When those decisions are made, the consequences can feel brutal. For 20 years, keepers at the St. Louis Zoo worked to understand the habits of endangered Mhorr gazelles, a graceful kind of antelopes, in their care. The animals had been squeezed out of the grasslands that border the Sahara by increased cattle ranching. Eighteen babies were born at the zoo during that time, a healthy rate. But then with fewer than 50 Mhorrs left in zoos in North America, there was not enough genetic diversity to reproduce without a risk of inbreeding. So, in 2008, a North American advisory group on the viability of hoofed species recommended that the animals be phased out of North American zoos and space given to another subspecies of endangered gazelle with more promising prospects. Sea lions are doing fine in the wild for now, but the St. Louis Zoo, which is taxpayer subsidized, decided to spend $18 million on a new pool, expected to be completed next year, that will be filtered and ozonated for clarity. Why? Because sea lions are one of the most popular attractions and their home was decrepit. Money also had to be spent on new restrooms and extra parking, meaning that stated priorities like breeding space for endangered animals and a frozen pool for walruses were shelved. What is the main idea of this article? (A) Zookeepers have to make painful choices as to which endangered species to save. (B) Zoos are transforming their mission quickly enough from entertainment to conservation. (C) Zookeepers are playing the major roles in bringing endangered animals back from extinction. (D) Zoos are increasingly concerning themselves with conservation, but the effort has limitations.

What is the overall tone of the passage?

(A) heavy and defensive

(B) serious and informative

(C) personal and reflective

(D) assertive and persuasive

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