both
propeller
Blood cells are a part of blood. Blood is not a part of blood cells. Blood can't flow backward and forward within blood cells. Blood cells can flow backward and forward within blood.
An ollie is a skateboard trick. And an ollie is a vital part in almost every trick.
Eye.
of course you can!
the Pectoralis Profundus is found in the "chest" of quadrapeds, in their Thoracic. It is part of the Quadruped Sling, and works with the Serratus Ventralis muscle to allow forward and backwards movement for quadrupeds of the forelimbs.
Its the wooden bit which you stand on. The main part of the board.
Street Luge
It is called the trucks
It is called the trucks
Its the forward part of the boat
"Backwards" is an adverb: "The car moved slowly backwards along the street."