$$ extbf{Solution:}$$ $$ullet$$ Bacterial diseases can be transferred from an infected person to a healthy person through air or contaminated food. $$ullet$$ Bacterial diseases which spread out through the medium of air are Whooping cough (caused by $$Bordetella$$ $$pertussis$$) and Tuberculosis (caused by $$Mycobacterium$$ $$tuberculosis$$). $$ullet$$ Contaminated food or water can also act as the medium of bacterial diseases like typhoid and botulism. $$ullet$$ Typhoid is caused by rod-shaped gram-negative bacteria $$Salmonella$$ $$typhi$$ and botulism or food poisoning is caused by rod-shaped gram-positive bacteria $$Clostridium$$ $$botulinum$$.