21.   It challenged accepted theories about intelligence development.

22.   The most accepted theory today is that billions of years ago, the mountains probably lay under the sea.

23.   The revolution in undergraduate teaching launched by Hutchins, Adler and their colleagues at Chicago challenged accepted modern educational theory.

24.   W.D. Hamilton, who devised a widely accepted theory to explain the evolutionary basis of altruism, died Tuesday of malaria, which he contracted in the Congo.