Final answer:
The popularity of the giant panda exhibit at the National Zoo is linked to the development of breeding and conservation programs after changes in zoo practices due to CITES and the Endangered Species Act in 1973.
Step-by-step explanation:
The popularity of the giant panda exhibit at the National Zoo can be traced back to the development of breeding and conservation programs following significant changes in zoo practices over the last 50 years, including the signing of the Convention on International Trade in Endangered Species of Wild Flora and Fauna (CITES) and the passage of the Endangered Species Act in 1973. These initiatives have led to a decline in wild animal imports and a focus on the conservation of endangered species like the giant panda, which are now bred in captivity and sometimes reintroduced into the wild. The efforts of zoos in animal conservation, breeding programs, and research assist in creating sustainable populations and conserving wildlife habitats, significantly enhancing the public interest and visitor engagement with exhibits such as those of the giant pandas.