Final answer:
Dr. E sprayed the baby chicks with bacteria as part of a scientific experiment to study the effects of the bacteria on the chicks.
Step-by-step explanation:
The answer to the question, 'Why did Dr. E spray the baby chicks with bacteria?' is option B. As part of a scientific experiment. Dr. E sprayed the baby chicks with bacteria as part of a scientific experiment to study the effects of the bacteria on the chicks. This experiment was conducted to gather data and observe the response of the chicks to the bacteria spray.