A pathogen and a red blood cell are drawn to the same scale, with some features indicated - HSC - SSCE Biology - Question 9 - 2015 - Paper 1

To determine the type of pathogen, examine the structures depicted in the images. The pathogen has a cell wall, which is a characteristic feature of fungi and bacteria. Notably, red blood cells do not have cell walls; they only possess membranes. This helps differentiate the pathogen shown.

Considering the options:

• A virus (A): Viruses do not have cell walls; they consist only of genetic material enclosed in a protein coat.
• A prion (B): Prions are misfolded proteins and do not have a cellular structure.
• A fungus (C): Fungi typically have cell walls made of chitin, which aligns with the image provided.
• A bacterium (D): Bacteria also have cell walls but are generally prokaryotic and may have different structural characteristics.

Since the features shown indicate the presence of a cell wall, the best option here is (C) A fungus.