Answer:
What you do to determine the length of something
Once you have it, you want to share it. Once you share it, you donβt have it. What is it?
The more you have of me, the less you see. Who am I?
If you drop me I'm sure to crack. But give me a smile and I'll always smile back.
What can be white and yellow at the same time?
It flows out of the soil, It burns you if it boils, And holds us in its coils, More valuable than gold, As black as it is old.