Multiple choice

Which of the following is least likely to cause disease?

  1. algae

  2. viruse

  3. bacteria

  4. protozoa
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Algae are primarily aquatic photosynthetic organisms that rarely cause human diseases. In contrast, viruses, bacteria, and protozoa include many well-known pathogens responsible for illnesses ranging from colds to malaria. Note: option B has a typo (viruse should be virus).

Keep practicing — related questions