31. Its present-day length is 52 kilometres. 32. Ranger School was reduced to its current 61-day length of training, at 19.6 hours of training per day. 33. The gametophyte phase only produces gametes when day length is long; with shorter days these too reproduce asexually. 34. In equatorial climes, the change in seasons is not always perceptible and thus, changes in day length not remarkable. 35. This reproductive diapause is a result of shortening day lengths during larval development and seasonal variation in lipid levels. 36. Birds also are sensitive to day length , and this awareness is especially important as a cue for migratory species. 37. The northern extension to Ferris was later added on April 1, 1948, bringing FM 660 to its present-day length . 38. In addition to the required day length , monarchs in diapause must also have temperatures that promote the formation of eggs. 39. The contemporary industrialized world, which blazes with artificial illumination, has suppressed men's ability to react to changes in day length . 40. Flower production is related to increasing day length , and in general, plants produced the most flowers from December to March.
