Virus Envelope and Capsid Identification

Steps:

• Identify label 1 as the outer protein shell enclosing viral genetic material, known as the capsid.
• Identify label 2 as the surrounding membrane layer derived from host cell lipids.
• Match descriptions: capsid is protein-based, while the envelope consists of phospholipids.
• Confirm A aligns with standard enveloped virus anatomy.

Why A is correct:

• In enveloped viruses, the capsid (1) is a protein structure protecting the genome, and the envelope (2) forms from host-derived phospholipids per virology definitions.

Why the others are wrong:

• B: Reverses the components; capsid is protein, not phospholipids.
• C: Incorrectly describes capsid as phospholipid-based, which contradicts its protein composition.
• D: Misattributes protein origin to the envelope (2), which is lipid-derived.

Final answer: A