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Choose the correct statement. Hydra an...

Choose the correct statement.
Hydra and Adamsia both belongs to same class and exhibit only polyp from
Planula larva of Obelia is formed from polyp from
planula larva is ciliated and formed from zygote through cleavage
In most coelenterates fertilisation is external

A

Only (a)

B

(a) and (b)

C

© and (d)

D

Only (d)

Text Solution

AI Generated Solution

The correct Answer is:
To solve the question, we need to evaluate each of the provided statements about Hydra, Adamsia, Obelia, and coelenterates. ### Step-by-Step Solution: 1. **Evaluate Statement A**: "Hydra and Adamsia both belong to the same class and exhibit only polyp form." - **Analysis**: Hydra is a genus of small, freshwater organisms that exhibit both polyp and medusa forms, while Adamsia (sea anemone) also primarily exists in the polyp form but can have a medusa stage in some classifications. Therefore, this statement is **incorrect**. 2. **Evaluate Statement B**: "Planula larva of Obelia is formed from polyp form." - **Analysis**: The planula larva of Obelia can be produced from both the polyp and medusa forms. Since it is not exclusively formed from the polyp form, this statement is **incorrect**. 3. **Evaluate Statement C**: "Planula larva is ciliated and formed from zygote through cleavage." - **Analysis**: This statement is **correct**. The planula larva is indeed ciliated, which aids in its swimming, and it develops from a zygote through cleavage, which is a process of cell division. 4. **Evaluate Statement D**: "In most coelenterates, fertilization is external." - **Analysis**: This statement is also **correct**. Most coelenterates, including jellyfish and corals, typically exhibit external fertilization, where eggs and sperm are released into the water. ### Conclusion: - The correct statements are C and D. However, since the question asks for the "correct statement," we can conclude that both C and D are valid, but C is the most direct answer to the specific phrasing of the question. ### Final Answer: - The correct statement is **C: Planula larva is ciliated and formed from zygote through cleavage.**
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