31.   In hot weather evaporation can cause the oxygen level to drop.

32.   In mice, and now in people, he and others found that leptin levels did drop with starvation.

33.   In the Middle Ages, however, the level of craftsmanship dropped.

34.   It later decided that the pollution levels were not dropping fast enough, a reconsideration that has fueled speculation that the EPA will order some form of dredging.

35.   It usually strikes women after menopause, when estrogen levels drop.

36.   Lead in the environment is ubiquitous, but levels have dropped significantly since leaded gasoline and lead in paint were outlawed.

37.   Levels drop precipitously in menopause.

38.   Lights dim during the evening as voltage levels drop.

39.   Like most animals, we produce a lot of melatonin early in life, but our blood levels drop sharply around puberty and decline steadily as we get older.

40.   Maybe our intensity level dropped a bit.