Mr. Garcia is behaving abnormally, and doctors strongly suspect he has a brain tumor. Which medical imaging device—conventional X ray, CT, PET, ultrasound, or fMRI—would be best for precisely locating...

Mr. Garcia is behaving abnormally, and doctors strongly suspect he has a brain tumor. Which medical imaging device—conventional X ray, CT, PET, ultrasound, or fMRI—would be best for precisely locating a tumor within the brain? Explain your choice.

Billy was dicing vegetables for dinner and accidentally cut his finger. Which feedback system, positive or negative, is at work during the process of blood clotting? Explain your choice.