Contrasts

Compares how plants and animals vary when their environments are essentially the same except that one is hot and dry and the other cold, such as a hot river in India versus a cold river in Canada.

Describes the characteristics and activities of animals and fish that live along the shores and in the waters of rivers and oceans.

Compares how animals vary in the same environment when day turns to night, such as the shrikes, locusts, and sand vipers of the North African desert that give way to scorpions, desert hedgehogs, and jerboas at nightfall.