Multiple choice

Viruses show the sign of life only after entering the cells of living organisms because they have only

  1. nucleus

  2. cell membrane

  3. nucleic acid

  4. cytoplasm

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Viruses lack the machinery for metabolism and reproduction. They contain only genetic material (nucleic acid, either DNA or RNA) and require the host cell's machinery to replicate.