Animals need certain compounds for their growth and development. many of the compounds found in food are larger and more complex than the compounds required by an animal. how does the animal obtain the needed compounds? a. the animal's digestive system absorbs only the simple compounds present in food. b. the animal acquires the required compounds from other animals. c. the animal's digestive system breaks down the complex compounds into simpler compounds. d. the animal acquires the required compounds from air and water.