Can someone tell me what I should highlight for question number 1?

Why reason best illustrates why hershey and chase chose to use viruses in their experiment?

What is an endocrine function? (apex) a. esophageal glands release mucus into the esophagus b. salivary glands release saliva into mouth c. swear glands release sweat to the skin d. the pineal gland releases melatonin into the bloodstream

Which type of respiration takes place when there is no oxygen present