Q.How many shoot apical meristems are likely to be present in a twig of a plant possessing 4 branches and 26 leaves?

A shoot apical meristem sits at the very tip of each growing shoot axis — the main axis and every branch — and it is what allows that particular axis to keep elongating. Leaves, in contrast, do not carry their own apical meristem; they are produced laterally by the shoot apical meristem and simply grow to a fixed size. …

A shoot apical meristem is the actively dividing tissue located at the extreme tip of a stem axis; it is responsible for the primary growth (lengthening) of that particular axis and for laying down new leaf primordia and lateral buds along the way.

• Leaves are lateral outgrowths produced BY a shoot apical meristem — they are not themselves growing axes and do not carry a meristem of their own once formed, so the number of leaves (26 here) has no bearing on the count of meristems. …

Method: Drawing the Branching Tree and Counting Only the Growing Tips

Rather than reasoning about leaves and branches in the abstract, sketch a simple branching-tree diagram of the twig and count only the tips that are actively growing axes — this makes the leaf-count distractor visually obvious to ignore.

Draw it: put a single vertical line for the main shoot axis, and let 4 side-branches emerge from it at various points along its length. Along the main axis and the branches, scatter 26 small leaf-shaped marks wherever convenient — the exact positions don't matter for this count.

Now look only at the LINE ENDS (the tips of the drawn axes), not the leaf marks. Each drawn axis — the main stem plus each of the 4 branches — has exactly one tip, and it is only at a tip that a shoot apical meristem can sit (a meristem is a growing point, and growing points exist only where an axis is still elongating). The leaf marks you scattered are attached partway ALONG an axis, not at a tip of their own, which is a direct visual reminder that leaves do not carry independent apical meristems. …