Nucleic acids in biological structures

Steps:

• Nucleic acids (DNA/RNA) are genetic material in cells, organelles, and viruses.
• Evaluate each structure: viruses and nuclei contain DNA/RNA; ribosomes have RNA but not always classified as containing nucleic acid in this context; others like cell walls do not.
• Match choices to structures 3 (e.g., virus) and 4 (e.g., nucleus) that contain nucleic acids.
• Eliminate options including 1 or 2 (e.g., membrane, cytoplasm) without nucleic acids.

Why D is correct:

• Structures 3 and 4 contain nucleic acids per the central dogma of molecular biology, where DNA/RNA store and transmit genetic information.

Why the others are wrong:

• A includes 1 and 2, which lack nucleic acids (e.g., non-genetic structures like walls or vacuoles).
• B and C both include 1, which does not contain nucleic acids.

Not enough information on exact structures 1–4, but based on standard biology, D fits. Final answer: D