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Choose the correct statement. a. Hydra...

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

A

Only (a)

B

(a) and (b)

C

(c) and (d)

D

Only (d)

Text Solution

AI Generated Solution

The correct Answer is:
To solve the question, we need to evaluate each statement provided and determine which one is correct. ### Step-by-Step Solution: 1. **Evaluate Statement A**: - Statement: "Hydra and Adamsia both belong to the same class and exhibit only polyp form." - Analysis: Hydra and Adamsia (also known as sea anemones) both belong to the class Hydrozoa. However, while Hydra exhibits only the polyp form, Adamsia can exhibit both polyp and medusa forms. Therefore, this statement is **incorrect**. 2. **Evaluate Statement B**: - Statement: "Planula larva of Obelia is formed from polyp form." - Analysis: The planula larva of Obelia is not formed exclusively from the polyp form; it can also arise from the medusa form. Therefore, this statement is **incorrect**. 3. **Evaluate Statement C**: - Statement: "Planula larva is ciliated and formed from zygote through cleavage." - Analysis: The planula larva is indeed ciliated and is formed from the zygote through cleavage. This statement is **correct**. 4. **Evaluate Statement D**: - Statement: "In most coelenterates, fertilization is external." - Analysis: In many coelenterates, fertilization occurs externally, especially in the medusa stage. This statement is also **correct**. ### Conclusion: Based on the evaluations: - Statement C is correct. - Statement D is also correct. Thus, the correct answer is that both statements C and D are correct. ### Final Answer: C and D are correct.
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