Final answer:
A leaf that allows some light to pass through but not all is described as translucent. This is because leaves are adapted to absorb sunlight for the process of photosynthesis.
Step-by-step explanation:
If light passes through a leaf hanging on a tree, but not all of it, this indicates that the leaf is translucent. A translucent material allows some light to pass through, but not all, and objects on the other side cannot be clearly seen through it.
This phenomenon occurs because leaves are designed to absorb some sunlight for photosynthesis, a process that converts light energy into chemical energy stored in sugars. In contrast, objects that are transparent allow light to pass through entirely, making things behind them clearly visible, while opaque materials do not permit any light to pass through.