71.   Of greater significance are differences that occur in the difficulties and constraints in the utilisation of the basic resources.

72.   One possibility is that some superior form of modifiability occurred in the smell-brain, and I shall return to this later.

73.   Other meteor storms have occurred in recorded history.

74.   Other unforeseen events also occurred in my family.

75.   Peat bogs, nearly all of which occur in northern latitudes.

76.   Perhaps the greatest deficiencies in the relationship between education and industry occurred in the training and recruitment of middle management.

77.   Petroleum occurs in natural deposits beneath the surface of the earth.

78.   Politics does not occur only in voting booths or demonstrations.

79.   Possibly dinosaurs living in the latter phase had developed complex social structures, as today occurs in some reptilian genera.