Multiple choice

Infectious agents do not spread through _________.

  1. vectors

  2. physical contact

  3. air

  4. vaccines

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

Vaccines contain weakened or killed pathogens (or their parts) to stimulate immunity without causing disease. They are preventive tools that stop infections rather than spread them. The other options (vectors, contact, air) are all valid transmission routes for infectious agents.

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