All questions of Adaptations and Variations for Grade 3 Exam

Fixed aquatic plants, like water lilies, have broad leaves with a waxy surface that helps them float on the water. The waxy coating keeps the leaves dry and prevents them from rotting.

A habitat provides everything an organism needs to survive, including food, water, shelter, and appropriate living conditions. For plants, this means having the necessary resources to grow and reproduce, even in varied and extreme environments like deserts, mountains, and underwater regions. Adaptations help plants thrive in these diverse habitats.

Roses use thorns to scare off animals that might eat them, which is a form of adaptation. This physical feature helps the plant protect itself from being consumed by herbivores, ensuring its survival and ability to reproduce.

Understanding Hilly Trees like Pine
Hilly trees, particularly pines, are fascinating plants that exhibit unique characteristics. Let's analyze the statements provided to identify which one is false.
Statement Analysis
- a) They do not have flowers.
- This statement is true. Pines are gymnosperms, meaning they reproduce using cones instead of flowers.
- b) They are dome shaped.
- This statement is false. While some trees may have a dome shape, pines typically have a more conical or pyramidal shape, especially when they are young. Their branches extend outward and upward, creating a distinctive silhouette that is not dome-like.
- c) They are conifers.
- This statement is true. Pines belong to the conifer family, which means they bear cones and have needle-like leaves.
- d) Their leaves are needle-shaped.
- This statement is also true. Pine trees have long, slender leaves that resemble needles, which help reduce water loss and withstand cold climates.
Conclusion
In summary, the false statement among the options is that hilly trees like pines are dome-shaped. Instead, they have a conical shape, making them easily recognizable in forests and hilly areas. Understanding these characteristics helps us appreciate the adaptability and beauty of pine trees in their natural habitats.

Adaptation of Hydrilla Leaves
Hydrilla is a submerged aquatic plant that has specialized adaptations that allow it to thrive underwater. One of the most important characteristics of Hydrilla leaves is their thin and narrow shape.
Reason for Thin, Narrow Leaves
- Hydrodynamic Shape: The thin and narrow leaves reduce resistance as the water flows around them. This shape helps prevent damage from currents and allows the plant to stay anchored to the substrate.
- Efficient Light Capture: Being narrow enables Hydrilla to capture sunlight effectively, even in deeper waters. It allows the plant to maximize light absorption, which is crucial for photosynthesis.
- Gas Exchange: The thin structure facilitates easier gas exchange through the leaf surface, allowing the plant to take in carbon dioxide and release oxygen, even underwater.
Comparison with Other Leaf Types
- Broad and Flat Leaves: While they can capture more light, they may not be as efficient underwater due to increased drag.
- Thick and Fleshy Leaves: These are generally heavier and may not be well-suited for underwater life where buoyancy is essential.
- Spiny and Sharp Leaves: These adaptations are more defensive and do not contribute to the efficiency of underwater survival.
Conclusion
In summary, the thin and narrow leaves of Hydrilla are perfectly adapted for life underwater, allowing the plant to thrive in its aquatic environment. This unique shape provides advantages in terms of light absorption, gas exchange, and reduced water resistance, making it a successful aquatic plant.

Floating plants like duckweed have spongy leaves filled with air spaces, which help them float on the water. This makes it easier for the plant to get sunlight and stay stable on the water surface.

Fixed aquatic plants, such as water lilies, have stomata on the upper side of their leaves to take in air. This is important because their leaves float on the water, so having stomata on top allows them to get the carbon dioxide they need for photosynthesis.