What is the main verb in the sentence “researchers concluded this when they studied injury rates at 100 high schools

Aclear technical document includes which element? a.complex sentence structure b.section headings c.abstract technical vocabulary d. long paragraphs

Aprimary source: a- may be biased b- is never biased c- cannot possibly have bias d- none of the above

In a series of experiments, hershey and chase radioactively labeled dna and protein in viruses and then used labeled viruses to infect bacteria. hershey and chase's experiments definitively showed that a. dna and not protein is the genetic material. b. dna and protein work together as a cell's genetic material. c. protein and not dna is the genetic material. d. neither dna nor protein act as a cell's genetic material