Man probably could not live without the help of animals. The (1) ______ of animals in the balance of nature ranks as their most important service to (2) ______. Animals also serve man by (3) ______ him with many foods and other useful products. Without animals, man (4) ______ have no meat, milk, eggs, or honey ; or wool, fur, or silk. For thousands of years, man has caused changes in the (5) ______ kingdom. He has tamed many kinds of animals and used (6) ______ for food and clothing. He has killed or driven away animals (7) _______ once attacked him or Interfered with his use of land. Today, he tries to (8) ______ many kinds of animals that are in danger of dying (9) _______. Like man, most plants depend (10) _______ animals for many of their basic needs. Without animals, many (11) ______ could not easily reproduce. For example, many plants with flowers depend on bees and (12) _______ insects to carry their pollen from plant to plant. Many oak trees grow from acorns that squirrels bury and then forget, or (13) _______ acorns that deer step on and push deep into the soil. Birds often fly from one place to another with seeds clinging to (14) ______ feet. The (15) _____ may sprout a great distance from the parent plants.