Why should we not put a pin or pencil in our ears?

Name the nerve which carries electrical impulses from the cochlea of ear to the brain.

What is the name of passage in outer ear which carries sound waves to the ear-drum?

What type of scans are used these days to monitor the growth of developing baby in the uterus of the mother?

How is an ultrasound scan for fetus (unborn baby) better than aX-ray?