I'd say stone tools. Stone can be chiseled or left alone and be used as a weapon to defend one's self, or as a way of getting food.
Answer:
As you might think, bacterial infections are caused by bacteria, and viral infections are caused by viruses. Perhaps the most important distinction between bacteria and viruses is that antibiotic drugs usually kill bacteria, but they aren't effective against viruses.
Explanation:
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Effects on fish, micro blooms
D all of the above would be the correct answer
