The diagram illustrates a section of a leaf cut across its width. What are the chief functions of the three labelled regions?
- Aregion 1: photosynthesis; region 2: gas exchange; region 3: transport
- Bregion 1: transport; region 2: photosynthesis; region 3: gas exchange
- Cregion 1: transport; region 2: gas exchange; region 3: photosynthesis
- Dregion 1: gas exchange; region 2: transport; region 3: photosynthesis