if you ride your bike around the block, returning to the exact point where you started, your displacement is m?

Zero

Explanation:

If you ride a bike around the block and return to the exact point where you started, your displacement is zero.

By definition, displacement involves changing an object from its original position. No matter how far or for how long a body moves, if it returns to the position it started from, it has not been displaced at all. This means that the body has zero displacements.

1 a

2 d

3 a

4 c

explanation:

"record the time to complete a chemical reaction" would most likely be part of a lab procedure.