Answer: Taking antibiotics to often and mutation in bacterial gene
Explanation:
The other two possible reasons that can cause the antibiotic resistant gene in the body is the taking antibiotics too often.
The antibiotics are taken too often that the body becomes resistant and the bacterial species are not killed by the antibiotics.
The second cause is that the bacteria might mutate and becomes resistant to the bacterial genome. In this case the antibiotics does not affects the bacterial species.
