The diagram presents a cross-section of a leaf. What are the structures P, Q, R and S?
- AP: chloroplast; Q: phloem; R: palisade tissue; S: xylem
- BP: cuticle; Q: xylem; R: chloroplast; S: stoma
- CP: phloem; Q: palisade tissue; R: cuticle; S: stoma
- DP: xylem; Q: chloroplast; R: phloem; S: cuticle