Question

Sol. Key concept: Fibonacci relationships occur in spiral phyllotaxis.

Phyllotaxis is the arrangement of leaves on a stem. In many plants with spiral phyllotaxis, successive leaves arise at a divergence angle close to 137.5°, the golden angle. This distributes leaves around the stem and can reduce overlap.

Common phyllotactic fractions include 1/2, 1/3, 2/5, 3/8 and 5/13; their numerators and denominators are drawn from successive Fibonacci numbers. Thus, the conventional answer is leaves, option (b).

Correction / clarification: Fibonacci patterns are not exclusive to leaves: spiral arrangements of florets or seeds in some inflorescences also show them. Option (b) is the intended phyllotaxis answer, but the broad wording does not make (d) biologically impossible.