A suitable caption for the diagram is: Transverse section of a dicotyledonous stem.

Here are the answers to Question 3:

3.1
A suitable caption for the diagram is: Transverse section of a dicotyledonous stem.

3.2
The identified parts are:

• 1: Cuticle
• 2: Epidermis
• 3: Collenchyma
• 4: Cortex parenchyma
• 5: Endodermis (Starch sheath)
• 6: Pericycle
• 7: Phloem

3.3
The functions of the parts are:

• 8 (Vascular cambium): Produces secondary xylem and secondary phloem, leading to secondary growth (increase in stem girth).
• 9 (Xylem): Transports water and dissolved minerals from the roots to the rest of the plant.

3.4
The two components that make up part 10 (Pith) are:

• Parenchyma cells
• Intercellular air spaces

3.5
Two parts where starch is stored are:

• 4 (Cortex parenchyma)
• 10 (Pith parenchyma)

3.6
The cells indicated by number 6 (Pericycle) in a dicot stem are often sclerenchymatous. Their characteristics include:

• Thick-walled.
• Lignified.
• Provide mechanical support.