J.C. Carmichael, age 17, of Grand Forks, N.D., for his question:

WHAT IS EXOBIOLOGY?

Exobiology is the branch of biology that specializes in the search for and study of life elsewhere in the universe. Exobioloqists try to apply their ideas of how life on the earth originated to discover and study life on other planets.

Exobiologists try to discover if the chemical and physical factors that controlled the origin of life on the earth are the same on other planets. They also want to know if the principles of evolution, or gradual development, that may be responsible for life on the earth can be found on other celestial bodies.

In their investigations, exobiologists rely heavily on organic chemistry involving animals and plants. Extremes of environment, such as heat, cold, mountains and desert, are also important in predicting the survival and evolution of living organisms.

Exobiologists also study fossil records. They are developing automated instruments that can perform chemical and biological experiments on other planets. This information will then be analyzed in earth laboratories.