We can maintain a healthy digestive system by doing all the following. Which one is not true?

Here are the solutions to the questions: 18. Living things are broadly categorized into plants and animals. Soil, stones, and water are non-living components. The best answer is C. plants and animals. 19. Invertebrates are animals that do not possess a backbone. Vertebrates are animals that do have a backbone. A. Toads are amphibians, which are vertebrates (they have a backbone). B. Worms are invertebrates. C. Houseflies are insects, which are invertebrates. D. Butterflies are insects, which are invertebrates. The question asks for the one that is not* an invertebrate. The best answer is A. toads.