Milton Lewin, ale 9, of Tucson, Arizona, for his question:

Which is the world's largest zoo?

The largest one may be the huge outdoor zoo near London, England. We cannot be sure because the Chinese had a big zoo at least 3,000 years ago. We know that they still have at least one big one  but they have not told us how big it is. At the English Zoo, the animals roam around 650 sprawling acres. Naturally there are unclimable fences and unjumpable ditches along the roadsides. At least around the homes of the bad tempered beasties who might try to eat the visitors.

An honest goodness zoo must keep and tend a variety of wild animals for public display. Safari lands do not count as true zoos because the lions and such roam freely outdoors, as they do in the wild. Our wildlife refuges and sanctuaries are not zoos either. One of the world's most famous zoos is in San Diego, There, amid lovely flowering gardens, 4,000 pampered captive animals are on display for the lucky visitors to admire.