31.   If modern humans sprang from Africa, then the Far East Homo erectus was probably an evolutionary dead end, though a few scientists still think otherwise.

32.   If confirmed, the new work would mean that human missions to Mars could be more technically challenging than some scientists had thought.

33.   If we have sufficient warning, most scientists think, there are ways we could prevent a collision.

34.   In a theory that now seems laughable, scientists once thought asthma was a psychological illness.

35.   In fact, many scientists have thought the short muscles must be the evolutionary vestiges of longer muscles that lost their usefulness over time.

36.   Initially, Gombe scientists thought that Goblin was just being a typical aggressive male expressing his dominance.

37.   Integrelin is part of what scientists think may be a major new class of drugs designed to treat blood clots.

38.   Leading scientists think this new field with the funny name could be the next big thing in biotechnology.

39.   Mars is now cold and desertlike, but many planetary scientists think that large oceans may have existed in times when it was warmer and wetter.

40.   Medical scientists thought they understood multiple sclerosis.