When measuring an object with a ruler, the end of the object should be lined up with the the ruler. end 0 mark 1 mark middle

0 Mark

Explanation:

For all the measurements that we make we always need some reference to find the value of the reading

So all the scales have its reference marked as 0 mark

When we put one end of our measurement at that reference mark then the other end of the measurement will give the reading of our measurements.

so here the correct answer should be

0 MARK

c because the action was the roller coaster reaches bottom of hill (action) reaction would be blood tends to drain away from head

hope this !

i think the answer is a, hope this : )