Which of the following statements are correct regarding the process of RNA interference?
(i) RNAi has been used to prevent nematode infestation of tobacco plants.
(ii) RNAi takes place in all eukaryotic organisms as a method of cellular defense.
(iii) The method involves silencing of specific mRNA using a complementary dsDNA molecule that binds and prevents the translation of mRNA.
(iv) Using retrovirus vectors, nematode-specific genes were introduced in the host plant.

detailed solution

Correct option is A

A novel strategy was adopted to prevent  nematode Meloidegyne incognitia to infects the roots of tobacco plants which was based on the process of RNA interference (RNAi). RNAi takes place in all eukaryotic organisms as a method of cellular defense. This method involves silencing of a specific mRNA due to a complementary dsRNA molecule that binds to and prevents translation of the mRNA (silencing). Using Agrobacterium vectors, nematode-specific genes areintroduced into the host plant.