Patricia Hammond, age 11, of Pittsburgh, Pa., for her question:

What is the world's oldest living thing?

The animal with the longest life span is thought to be the tortoise. This fellow becomes an old t!Mer when he reaches his 100th birthday. The old turtle is a mere infant compared with certain members of the plant world. And the oldest plants, so far as we know, are trees. For a long time the Sequoia redwoods of California were thought to be the oldest of earth's living things. Many of these magnificent giants were alive and growing before the time of Julius Caesar. Then the ages~of certain dumpy, gnarled bristlecone pines Were checked, and some of them were found to be almost 1,000 years older than the ancient Sequoias. They also grow in California, just a few miles from the old redwood groves. So far as We know these dumpy bristlecone pines are the oldest living things on earth.