DENDROLOGY

Detailed explanation-1: -Explanation: The oxygen we breathe consists of molecules. Each molecule consists of two oxygen atoms joined together, so we write its formula as O2 .

Detailed explanation-2: -The Symbol of oxygen is ‘O’ and the formula for oxygen is ‘O2’. The difference between the symbol and formula is that the symbol ‘O’ is a free oxygen atom whereas O2 is two oxygen atoms chemically bound to form an oxygen molecule.

Detailed explanation-3: -Diatomic oxygen (O2) is the most common and stable form of oxygen, and it is the form that exists under standard temperature and pressure. It is a colorless, odorless gas that constitutes about 20.8% of the Earth’s atmosphere.