Carbon-14 is a dating technique used to estimate the age of the bone which is less than 40,000 years old.
When an organism dies the carbon 14 is converted into nitrogen 14 so, we can estimate the age of the bone.
This method is used by the archaeologist to find the age of the dead and decay animals present inside the earth's surface to study the earth and creature who have lived on earth.
Tube 1 doesn't contain an organism so it can't be that one. Both a snail and a plant are considered an organism, and cellular respiration occurs in almost any organism's cells
