Heavy accumulations of these cool water droplets form clouds. The darker the cloud, the more concentrated the water droplets. Eventually, when enough water droplets accumulate, they form rain, which is pulled to the earth by gravity. Animals and plants are both involved in the water cycle. Plants possibly play a greater role than animals since plants absorb water through their roots and give off water vapor from their leaves by transpiration.
All animals depend upon water to live.
They drink water and give off water through excretion of liquid wastes and through perspiration. Instruct students to use Water Cycle Worksheet handout to trace the steps involved. Direct students to follow the arrows, to explain each step in the cycle, and to give the names of the types of water involved or the states of the water as it passes through the cycle. Lead the class in a discussion regarding the predictions of what will happen to the water cycle due to the slow warming of the earth, the melting of the polar ice caps, and the resulting thermal expansion of the seas. Cycles in Nature pp.