Unit 2: Diversity in the Living World — Let us enhance our learning (Answers)
Answer: b) reticulate venation – tap root – two cotyledons
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A (Aquatic) Dolphin Whale |
C (Both) Frog Crocodile |
B (Terrestrial) Horse Sheep Squirrel Earthworm Pigeon Tortoise |
| Plant | Group | Reason |
|---|---|---|
| Rose | Shrub | Hard, woody stem branching close to the ground |
| Mango | Tree | Tall, hard, thick stem with branches higher up |
| Wheat | Herb | Short plant with soft, green, thin stem |
| Coconut | Tree without branches | Tall, hard stem but no side branches |
| Group | Type of seed | Type of root | Examples |
|---|---|---|---|
| A | Dicot | Taproot | Mango, Hibiscus, Chickpea |
| B | Monocot | Fibrous roots | Wheat, Maize, Lemongrass |
(a) Plants of group A also have reticulate venation in their leaves and their seeds split into two cotyledons.
(b) Plants of group B also have parallel venation in their leaves and their seeds have only one cotyledon.
Similarities: Both have four legs, horns, and a similar body shape, and both eat grass.
Differences: The mountain goat has long, thick, shaggy fur while the plains goat has short, smooth fur.
Reason: The mountain goat lives in cold, high regions, so its thick fur is an adaptation to keep it warm. The plains goat lives in warmer areas, so it does not need thick fur.
| Feature | Wheat | Kidney bean |
|---|---|---|
| Cotyledon | One (Monocot) | Two (Dicot) |
| Root type | Fibrous root | Taproot |
| Leaf venation | Parallel venation | Reticulate venation |
Radish has a taproot (one thick main root growing deep into the soil). Since radish is a dicot plant, its leaves show reticulate venation.
A = A plant with reticulate venation (dicot) — Example: Mango / Hibiscus
B = A plant without reticulate venation, i.e. parallel venation (monocot) — Example: Wheat / Grass
The duck has webbed feet (skin joining the toes), while the pigeon has separate, thin toes without webbing. The webbed feet help the duck to paddle and swim easily in water, which the pigeon cannot do.
Answer: a) Both A and R are true, and R is the correct explanation of A
Answer: This classification is incorrect. Plants with parallel venation and fibrous roots are features of monocot plants, not dicots. Dicot plants have reticulate venation and taproots.
Cutting down forests destroys the habitats of many plants and animals, so they lose their homes and food. This leads to loss of biodiversity, less rainfall, more soil erosion, and increased pollution in our surroundings. We can address this by planting more trees, protecting existing forests, avoiding wastage of paper and wood, and creating awareness among people about the importance of forests.
Sanjay can ask:
- Is the stem of the hibiscus plant hard and woody?
- Do the branches arise close to the ground?
- Is the plant shorter than a tree?
If the answers are yes, then it confirms that hibiscus is a shrub.
| Group A: Give birth to young ones (Viviparous) | Group B: Lay eggs (Oviparous) |
|---|---|
| Cow, Bat, Whale | Cockroach, Pigeon, Tortoise, Fish, Grasshopper, Lizard |
