Sam made some observations of how the leaves of some plants adapt to their environment. He recorded his observations in the table shown below.
| Plant | Adaptation | Function |
| X | air spaces in leaves | helps the plant to float |
| Y | waxy leaves | prevents water from collecting on the leaves |
| Z | needle-like leaves | reduce water loss |
Based on the information given above, which of the following correctly describes the reason for the adaptation of leaves X, Y and Z?