When Dr. Jeff jumps on a skateboard and uses the fire extinguisher to move, which of these does he change to move BACK to where he started?
A. amount of force
B. type of force
C. direction of force
D. Skateboard wheels

The correct option is C) direction of force

Explanation:

In the terms of physics, force can be described as a push or pull on an object which allows the object to either move forward or backwards or in other directions.

When Dr. Jeff uses the fire extinguisher of the skateboard to move forward, he will require the same force to move backward but in the opposite direction. Hence, for moving backwards, the only thing required by Dr. Jeff to move backwards will be the direction of the force.

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enzyme active site and substrate specificity

enzymes bind with chemical reactants called substrates. there may be one or more substrates for each type of enzyme, depending on the particular chemical reaction. in some reactions, a single-reactant substrate is broken down into multiple products