Answer:
Your friend is correct.
Step-by-step explanation:
It is given that your friend says that you must always line up objects at the zero on a ruler. Your cousin says it does not matter.
We need to decide who is correct.
When we measure the length of any object we have to line up objects at the zero on a ruler, so that mark on the rules along the other end of the object represents the length of the object.
Let we have a pencil of length 5 cm.
If we place the rules on 0, then 5 is the mark on the rules along the other end of the pencil. So, height of the pencil is 5 cm.
If we place the rules on 1, then 6 is the mark on the rules along the other end of the pencil. So, height of the pencil is 6 cm, which is not correct.
Therefore, your friend is correct.