The table shows four features that can be used to distinguish between types of pathogens - HSC - SSCE Biology - Question 15 - 2016 - Paper 1

To determine the correct row, let's analyze each feature against the characteristics of prions and protozoans:

1. Contains DNA:

   • Prions do not contain DNA; they are misfolded proteins.
   • Protozoans do contain DNA as they are single-celled organisms.
   • Therefore, row (A) is incorrect.

2. Cellular:

   • Prions are acellular; they do not consist of cells.
   • Protozoans are cellular organisms.
   • Therefore, row (B) is incorrect.

3. Can reproduce:

   • Prions cannot reproduce by themselves; they induce misfolding in existing proteins.
   • Protozoans can reproduce, primarily through asexual reproduction.
   • Therefore, row (C) is incorrect.

4. Composed of protein:

   • Prions are entirely composed of protein.
   • Protozoans, however, are composed of various biomolecules including carbohydrates, proteins, and nucleic acids.
   • Therefore, row (D) is incorrect for protozoans but correct for prions.

Given these analyses, the correct option that fits the provided characteristics is (B): Cellular. Protozoans are cellular while prions are not.