Let's solve each question from the worksheet step by step and explain the answers clearly.
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I. Answer the following.
1. How are the spines in a cactus different from the prickles on a rose plant?
Answer:
Spines in a cactus are modified leaves that help reduce water loss by minimizing surface area and provide protection from animals. They also help shade the plant from intense sunlight. In contrast, prickles on a rose plant are outgrowths of the stem (not modified leaves) and are primarily for protection against herbivores. Unlike cactus spines, rose prickles do not play a role in reducing water loss or photosynthesis.
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✔ Explanation:
> - Cactus spines =
Modified leaves → Adaptation to dry environments.
> - Rose prickles =
Stem modifications → Defense mechanism only.
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II. Think and Answer.
a. Why do the leaves of water lilies and lotus have stomata on the upper surface?
Answer:
Water lilies and lotus are aquatic plants whose leaves float on the surface of water. The lower surface of the leaf is in contact with water, so it cannot exchange gases effectively. Therefore, the stomata (tiny openings for gas exchange) are located on the
upper surface of the leaf, which is exposed to air. This allows them to take in carbon dioxide for photosynthesis and release oxygen efficiently.
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✔ Explanation:
> - Stomata need air for gas exchange.
> - Since the bottom is submerged, stomata must be on top to access air.
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b. Why are oak and maple trees called deciduous trees?
Answer:
Oak and maple trees are called
deciduous trees because they shed their leaves annually, usually in autumn, before winter. This helps them conserve water and energy during cold months when photosynthesis is not efficient due to low light and temperature. By losing their leaves, these trees reduce water loss through transpiration and survive harsh winters.
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✔ Explanation:
> - "Deciduous" means "falling off" (from Latin *deciduus*).
> - These trees drop leaves seasonally → adaptation to seasonal climates.
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✔ Summary of Key Concepts:
| Plant | Adaptation | Reason |
|------|------------|--------|
| Cactus | Spines (modified leaves) | Reduce water loss & protect from animals |
| Rose | Prickles (stem outgrowths) | Protection only |
| Water lily / Lotus | Stomata on upper surface | To access air for gas exchange |
| Oak / Maple | Deciduous (lose leaves) | Survive winter by conserving water and energy |
These adaptations show how plants evolve structures suited to their environments.
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Parent Tip: Review the logic above to help your child master the concept of plant adaptation worksheet.
