Final answer:
Pathogenic bacteria cause disease or infection. They can spread through contact or contaminated food and water. Antibiotics kill both harmful and beneficial bacteria in the body. Correct option is D.
Step-by-step explanation:
The question asks what pathogenic bacteria do. Pathogenic bacteria are known for causing disease or infection in their hosts. While many bacteria are harmless and even beneficial to human health, pathogenic bacteria can spread through various means such as direct contact, contaminated food, water, or surfaces, and can lead to a variety of illnesses.
Examples of bacterial diseases include tetanus, syphilis, and food poisoning. It's also important to note that while antibiotics are used to kill bacteria causing illness, they can also destroy the good bacteria that protect the body from infection.