In 1898 Friedrich Loeffler and Paul Frosch found evidence that the cause of the highly contagious hoof-and-mouth disease in livestock was a microscopic infectious particle. It was discovered that this particle requires a host cell to reproduce. Which pathogen is most likely responsible for causing the hoof-and-mouth disease in livestock? Your A virus because it requires a jost cell to reproduce B protist because it is microscopic C fungus because it infects livestock

A. virus because it requires a host cell to reproduce

Explanation:

This is probably a viral disease (and from an internet search, I can confirm that it is). A good way to understand this is that from the information given, we should infer that it's a viral disease: viruses are microscopic, infectious, and need a host cell. Protists and fungi just aren't good answers, because protists don't infect people usually, and fungi are not always microscopic.

uh two lol

substitution is the answer in this case