Natural selection. Only spiders that were more resistant to the pesticide lived through the first spraying of the pesticide, thus we're the only ones that could reproduce. This in turn made the offspring of the previous generation more resistant as well; thus making the pesticide less effective.
Answer:
Organic molecules produced from spontaneous synthesis or from meteorites
Explanation:
Switch to anaerobic respiration
Answer:
A vaccine activates our immune system without making us sick. Many dangerous infectious diseases can be prevented in this simple and uncostful
drug .Vaccines have eliminated some of the most dangerous, fatal diseases in human history.