The cortex of a herbaceous stem is made up of

Step 1: Analyze the question The question asks which tissues make up the cortex of a herbaceous (soft, non-woody) stem. The cortex is the region between the epidermis and the vascular bundles.

Step 2: Explain the concept In a typical dicot herbaceous stem, the transverse section shows these layers from outside to inside:

1. Epidermis: a protective outer layer, usually covered by a cuticle.
2. Cortex: the region just beneath the epidermis, made of: • Collenchyma: a few layers just under the epidermis. Their cell walls are thickened with extra cellulose at the corners, which gives support and flexibility to young stems. • Parenchyma: thin-walled cells with intercellular spaces, found beneath the collenchyma. They store food and fill the bulk of the cortex.
3. Vascular bundles: arranged in a ring, each containing xylem, phloem and cambium. Sclerenchyma (the pericycle fibres) may cap the bundles.
4. Pith: parenchyma at the centre.

Step 3: Check the options

• A. Collenchyma and parenchyma: this matches the cortex. ✔
• B. Collenchyma and sclerenchyma: sclerenchyma is not a typical cortex tissue in a herbaceous stem. It is found around the vascular bundles or in the pericycle region. ✘
• C. Parenchyma and sclerenchyma: sclerenchyma is again not part of the cortex. ✘
• D. Pericycle and endodermis: these are the inner boundary of the cortex, not its main components. The endodermis is also poorly defined in stems. ✘
• E. Sclerenchyma and endodermis: ✘

Step 4: Answer The cortex of a herbaceous stem is made up of collenchyma and parenchyma, which is option A.

Exam tip: Remember the order "C-P" for the cortex: Collenchyma (outer, for support) then Parenchyma (inner, for storage). Sclerenchyma belongs with the vascular bundles and gives strength there.