What is a common characteristic of oxygen?

Oxygen is characterized as being odorless and essential to life, which underscores its critical role in biological processes. This gas is a vital component of the atmosphere and is required for cellular respiration in most living organisms. The absence of oxygen would result in the inability of cells to produce energy, leading to life-threatening consequences.

In contrast to other choices, the notion that oxygen is colored and heavy does not align with its physical properties, as oxygen is a colorless gas at room temperature and is not particularly heavy compared to many other gases. The statement that oxygen is only found underwater is misleading, as it exists abundantly in the atmosphere and is not limited to aquatic environments. Lastly, oxygen is not a liquid at room temperature; it is primarily a gaseous state under standard conditions. Thus, the essence of oxygen as odorless and vital to life makes it a fundamental element in both respiratory processes and overall ecological balance.