Unit 1

3. A virus is only about 100nm across.
4. All molluscs have soft bodies that are not divided into segments.
6. insects have a body that is clearly divided into a head, a thorax and an abdomen.
7. The eardrum of a mammal, like those of reptiles and birds, is deep inside the head, but all mammals have a pinna (flap) on the outside of the ear.
10. All living organisms need energy.
12. The adults of some amphibians, such as salamanders, live on land.
15. Every kind of living thing (but not necessarily every individual) is able to make new organisms like itself.
17. Some of them, such as crocodiles, spend a lot of time in water.
18. So far in this chapter, all the living organisms we have looked at have been animals.
19. Chemical reactions, often called metabolic reactions, take place inside the cells of every living organism.
20. like crustaceans, their body is divided into a cephalothorax and abdomen.
21. All organisms are able to move.
23. Earthworms are annelids, and so are the tube worms that you may see in rock pools on a beach.
24. They live in water, in soil, in food, in you and almost everywhere else you can think of.
25. However, their bodies are not divided into segments.

1. Birds are very closely related to reptiles, and, like reptiles, have scaly legs and holes leading to their eardrums.
2. All organisms need to take in substances from their surroundings.
5. Living organisms are sensitive to things around them.
8. They are arthropods with long, thin bodies made up many similar segments.
9. Their exoskeleton is usually especially strong, because it contains calcium salts that make it very hard.
11. They have fins to help them to move and balance.
13. Some of the nutrients that living organisms take in are used to help cells to grow, and to help to make more cells.
14. Long ago, fungi were classified as plants.
16. Perhaps the most familiar group of organisms is the vertebrates.
22. the living organisms that people are familiar with all have common names.