the hardest working horse is a appolosa. the hardest working muscle in your body is the heart. it pumps loads of blood through your body every second!
the largest organ i think is the digestive system, as in the gut. but the busiest and most hard working orgas is the heart.....what else is going to keep you alive?
The heart.
The strongest, hardest and largest bone in the human body is the femur, or your thigh bone.
heart is the busiest organ :) (lucent's general knowledge )
the heart
The hardest substance in the human body is tooth enamel.The enamel that coats your teeth is the hardest substance in the human body.enamel of your teeth?
Enamal is tha hardest part of human body..
The enamel on your teeth is the hardest substance your body produces or is made of.
The bone.
The jawbone.
calcium
I would say the heart, as he generally never stops.
Enamel is the hardest substance in the human body.
What do you mean by wildest? The hardest to catch, the hardest to tame? One of the hardest to catch and tame are lions. They are ferocious and vicious.