A flowering plant produces flowers that are functionally unisexual — bearing only pistils and no stamens. (a) Can such a plant reproduce sexually without external agents? Give a reason. (b) Identify two agents that could bring about pollination in such a plant and explain how each achieves this.
Generated by claude-sonnet-4-6 · 2026-06-26 01:06 · grounding rag
Model Answer
(a) No. Since the plant bears only pistils and no stamens, it cannot produce pollen. Without pollen, self-pollination is impossible, so it cannot reproduce sexually without external agents.
(b) Two agents that could pollinate such a plant:
- Wind: Wind carries pollen grains from stamens of another plant and deposits them on the sticky stigma of this plant, achieving cross-pollination.
- Animals (insects/birds): Animals visiting flowers for nectar pick up pollen from another plant's stamens and transfer it to the stigma of this plant while feeding.
Source: Chapter 7, Section 7.3.2 — Sexual Reproduction in Flowering Plants
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Explanation
- Part (a) tests whether you understand that a pistil-only flower lacks stamens, so no pollen is produced — self-pollination is ruled out entirely. Always state the reason clearly.
- Part (b) expects any two agents from the textbook list: wind, water, or animals. Briefly explain the mechanism for each — examiners look for "how," not just naming the agent.
- Key term to use: cross-pollination (pollen from one flower to another).
- Keep both agent explanations parallel and concise — one sentence each is enough for the marks available.