Problem: John is an amateur astronomer. He recently found two stars, star A and star B. Upon observation, he figured out that star A is a blue star, but star B is a red giant. He had to do some research to find out the differences between them. Which star would be less visible, star A or star B?

A: star A

Problem: Two old friends were both oceanographers. They were both researching the levels of marine pollution in Earth's oceans. Vic studied the Arctic Ocean, while Dan studied the Pacific Ocean. Which friend observed fewer fertilizers which cause marine pollution ?

A: Vic

Problem: Jackie and Mark are two friends who are spending a day at the beach. Jackie wants to go out on the boat to spend some time on the ocean, but Mark wants to lay out on the beach and relax. Since they can't agree, Jackie goes out on the boat alone while Mark stays behind on the beach. Is the air around Mark more or less dense than the air around Jackie?

A: less

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