the hand is the most used body part This person doesn't know what they are talking about... The tongue is the most used body part. These two guys have no idea, your eyes are the most used part of your body
The oxygen is actually used for everything the body does. It is used for movement of the muscles, some is carried to various body organs in order to work and does its job. the oxygen is the food of the body.
Lions are like us, they have most body parts like us. The lungs are obviously for their breathing. The heart is used for pumping blood through their body. Their jaws are to kill and rip the animals body parts.
Histamines are produced in the body when the body perceives something as a foreign body. Allergens also cause the production of histamines and hence antihistamines are used in case of an allergic attack.
The only time a human body is used as an investigatory project is if the person has given permission for their body to used by science. This gives the scientist permission to use their body to teach other students about the anatomy and other things.