26. Pickout an odd one regarding sexuality
1) Nereis
2)Hirudinaria
3) Pheretima
4) Lumbricus
Answers
Answer:
Nereis is the odd one out.
Explanation:
Nereis: At maturity, the body is transformed into a heteronereid or epitoke. Its body is full of gametes and its only function is reproduction.
Hirudinaria: Leeches are hermaphrodites. Each individual possesses well-differentiated male and female reproductive organs. Self-fertilisation does not occur instead cross-fertilisation is seen by copulation.
Pheretima: They are hermaphrodites. Reproduction can be either sexual or parthenogenetic. Pheretimas developmental stages are without the larval stage it takes place in the cocoons.
Lumbricus: They are hermaphrodites. Each one carries male and reproductive organs. While mating two of them will exchange sperm and fertilize each other's eggs.
Hence, Nereis is different from the others.
Answer:
The correct answer is (1) i.e. Nereis.
Explanation:
In the question we have asked about the odd with respect to sexuality .
(1) Nereis - is an annelid and its dioecious .Nereis is unisexual which means sexes are separate.
(2) Hirudinaria - is an annelid which is monoecious. Hirudinaria is bisexual which means male and female reproductive organs are present in same organism.
(3) Pheretima- also known as earthworm is an annelid , which is also bisexual.
(4)Lumbricus - is also an annelid and is bisexual.
So, we can conclude from the above statements that with respect to sexuality Nereis is odd one.
So , the correct answer will be (1) Nereis.