Given below are two statements :

Statement I : Transfer RNAs and ribosomal RNA do not interact with mRNA.
Statement II : RNA interference (RNAi) takes place in all eukaryotic organisms as a method of cellular defence.

In the light of the above statements, choose the most appropriate answer from the options given below :

Explanation of Statement I

Transfer RNAs (tRNAs) and ribosomal RNA (rRNA) do interact with messenger RNA (mRNA) during protein synthesis.

– tRNA carries a specific amino acid and contains an anticodon that base‑pairs with a three‑nucleotide codon on the mRNA strand. This pairing is essential for translating the genetic code into a polypeptide chain.

– rRNA forms the core of the ribosome. The ribosomal RNA creates the catalytic site (peptidyl‑transferase centre) and also binds directly to the mRNA, holding it in the correct reading frame as the ribosome moves along the transcript.

Because both tRNA and rRNA physically bind to mRNA, the claim that they “do not interact with mRNA” is false. Hence Statement I is **incorrect**.

Explanation of Statement II

RNA interference (RNAi) is a conserved cellular mechanism found in virtually all eukaryotic organisms.

– In RNAi, double‑stranded RNA (dsRNA) is processed by the enzyme Dicer into small interfering RNAs (siRNAs) or micro‑RNAs (miRNAs).

– These small RNAs guide the RNA‑induced silencing complex (RISC) to complementary mRNA targets, leading to their degradation or translational repression.

– The primary biological role of RNAi is to protect the cell against invasive nucleic acids such as viruses and transposable elements, thereby serving as a method of cellular defence.

Since RNAi operates in plants, animals, fungi, and protists, the statement that “RNA interference (RNAi) takes place in all eukaryotic organisms as a method of cellular defence” is **correct**.

Therefore, the most appropriate choice is: Statement I is incorrect but statement II is correct.