Direction: Read the following information carefully and answer the given questions.

The recent death of the last male northern white rhinoceros and the imminent extinction of the vaquita porpoise is a stark reminder we are not going to win every battle to save endangered species in the wild. We can rescue some from total extinction and have already but only with the help of zoos and aquariums. Wildlife populations are increasingly under stress from human activities and their impact on the environment. Population growth, habitat destruction and wildlife poaching whether for sustenance or profit are among the largest threats contributing to their extinction.

Rhino horn, for example, fetches upwards of US$60,000 per kilogram in countries where it is prized as a cure and status symbol. But this is bogus. Rhino horn is made of keratin, like our fingernails, and cannot cure disease. We need a planet-wide shift in thinking about how we value the wildlife resources within the limited intact ecosystems that remain. But many species cant wait that long.

If we accept that we will lose some battles to save species in the wild, how do we make sure we don't lose the war on extinction in the long term? One option is to establish populations in zoos and aquariums. When carefully managed, these populations serve as safety nets against species extinction. They buy us time until we sort out the human side of the extinction equation.

Captive populations have restocked wild populations and saved many species from extinction. The Puerto Rican toad, California condor, Scimitar-horned oryx, Amur leopard and the black-footed ferret wouldn't exist if it weren't for their captive-bred ancestors. In Canada, captive breeding helped save the Vancouver Island marmot. Wildlife biologists like myself continue to work with species declared extinct in the wild - the Kihansi spray toad, Panamanian golden frog, Micronesian kingfisher and Hawaiian crow. But we will have to wait until the threats, such as habitat loss and invasive species, that led to their extinction in the wild are neutralized before they can be reintroduced.