Problem: John wanted to see how he would fare in high altitude compared to ground-level. So, he first measured his responses in ground-level. He labeled this part of the study as case A. Then he board on an airplane to reach high altitude, and measured his responses there. He labeled this part of the study as case B. Now, John knows how he needs to prepare for a high altitude hiking. Which case would see higher air density, case A or case B?

A: case A

Problem: Tammy and Rob rode a tandem bike down the hill. They hit a large rock and fell. Tammy wound up in the hospital and was diagnosed with a serious brain injury. Rob suffered only a mild concussion. Which person had more problems with mental abilities?

A: Tammy

Problem: Two groups of tourists went on two different cruise ships Group J had some members contract Norovirus and hepatitis A, while group K got many cases of giardia and trichinella infections. Which group had more people with inflammation of the stomach?

A: Group J

Problem: Two teams studied two types of animals: team A studied predators, while team B studied grazers. They learned a lot from this experience. Which team learned less about deer?

A:
team A