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Assertion: Cnidarians exhibit two basic ...

Assertion: Cnidarians exhibit two basic body forms. The polyp is sessile and umbrella shaped and medusa is free-swimming and cylinderical form.
Reason: Cnidarians have a central gastro-vascular cavity with a single opening, hypostome on mouth.

A

IF both assertion and reason are true and the reason is the correct explanation of the assertion.

B

If both assertion and reason are true but reason is not the correct explanation of the assertion.

C

If assertion is true but reason is false.

D

If both assertion and reason are false.

Text Solution

Verified by Experts

The correct Answer is:
D
* Cnidarians exhibit two basic body forms. The polyp is sessile and cylinderical and medusa is free-swimming and umbrella shaped.
* Cnidarians have a central gastro-vascular cavity with a single opening,mouth on hypostome.
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Fill up with the suitable words Cnidarians exhibit two basic body forms called _a__ and __b__. The former is ___c___ and___d___ form whereas , the latter is ___e__ and __f___.

Mark te given statements True (T) or False (F) (i) All members of animalia are multicellular. (ii) Sponges exhibit tissue grade level of body organization (iii) A complete digestive system has two openings, mouth and anus. (iv) Annelids are pseudocoelomate animals. (v) notochord is an endodermally derived structure. (vi) all vertebrates are chordates. (vii) all chordates are vertebrates (viii) Polyps produce medusae asexually and medusae form the polyps sexually. (ix) Hooks and suckers are present in non parasitic flatworms (x) Lamprey dies after few days of spawning.

Knowledge Check

  • Cnidarians exhibits two basic body forms called polyp and medusa. The polyp represents

    A
    asexually reproducing, sessile , cyclindrical form
    B
    sexually reproducing free-swimming form
    C
    sexually reproducing cyclindrical form
    D
    asexually reproducing umbrella-shaped form

  • Coelenterata in which basic body form exhibit umbrella like appearance and are free swimming–

    A
    Polyp only
    B
    Medusa only
    C
    Both (1) and (2)
    D
    Obelia

  • Assertion :- Polyps produce medusae sexually and medusae form the polyps asexually. Reason :- Polyps and medusae are the common feature of different group of cnidarians.

    A
    If both Assertion & Reason are True & the Reason is a correct explanation of the Assertion.
    B
    If both Assertion & Reason are True but Reason is not a correct explanation of the Assertion.
    C
    If Assertion is True but the Reason is False.
    D
    If both Assertion & Reason are false.

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