Alternation of Generations in Cnidarians

Q. Assertion [A]: Obelia exhibits metagenesis.
Reason [R]: Obelia exists in both polyp and medusa form.

1. Both Assertion and Reason are true and Reason is the correct explanation of Assertion
2. Both Assertion and Reason are true but Reason is not the correct explanation of Assertion
3. Assertion is true but Reason is false
4. Both Assertion and Reason are false

Q. Alternation of generations is seen in

1. Aurelia
2. Adamsia
3. Hydra
4. Obelia

Q.

Metagenesis refers to

1. Metaphysic

2. Metamorphosis

3. Metagenesis

4. Metamerism

Q. Find out the incorrect statement(s).

I. Polyp is sessile and cylindrical like Adamsia

II. Medusa is umbrella shaped and free-swimming like Aurelia

III. Polyps produce medusae sexually and medusae form the polyps asexually

IV. Medusae produce polyps sexually

1. Only I
   
2. Only III
3. I and IV
4. II and III

Q. Metagenesis refers to:

1. Presence of a segmented body and parthenogenesis as a mode of reproduction
2. Occurrence of a drastic change in form during post-embryonic development
3. Presence of different morphic forms
4. Alternation of generation between asexual and sexual phases of an organism

Q. Which of the following members of phylum Coelenterata lack a sexual medusa stage?

1. Jellyfish
2. Hydra
3. Sea ginger
4. Sea raft

Q. Which of the following terms describe the life cycle of Obelia?

1. Metamerism
2. Metagenesis
3. Regeneration
4. None of these

Q. Medusa of Coelenterata is

1. sexually reproducing
2. free swimming
3. umbrella shaped
4. all of these

Q. Which of the following traits is not common for sea anemone and jellyfish?

1. A medusa as the dominant stage in the life cycle
2. Possession of a gastro vascular cavity
3. Sexual reproduction
4. Nematocysts present on the tentacles

Q. Consider the following statements during the alternation of generation or metagenesis in dimorphic cnidarians, the polyps are:
(1) Sedentary
(2) Free living
(3) Polyp forms the medusa sexually
(4) Polyp forms the medusa asexually
Which of the following given statements are correct?

1. 1, 3 and 4 are correct
2. 1, 2 and 3 are correct
3. 1 and 4 are correct
4. 2, 3 and 4 are correct