Which of the following is NOT a characteristic of fuel gas?

The option indicating fuel gas is "completely renewable" is not a characteristic of fuel gas. Fuel gas, which includes natural gas, propane, and other fossil fuel gases, is derived from non-renewable sources such as natural gas deposits and petroleum. These sources take millions of years to form and are not replenished on a human timescale, meaning once they are consumed, they cannot be restored within our lifetimes.

In contrast, characteristics such as being used for heating and serving as a source of energy for various applications highlight the practical uses of fuel gas. Additionally, noting that fuel gas is one of the most commonly utilized fossil fuels underlines its prevalence and significance in energy consumption patterns. Thus, the attribute of being "completely renewable" stands apart as it does not accurately reflect the nature of fuel gas, as it does not renew itself naturally and remains a critical aspect of fossil fuel energy resources.