Final answer:
The false statement among the options is that 'The Earth is flat.' Water is polar, stabilizes temperature, and is essential for life, but it is not the most abundant molecule in Earth's atmosphere, which is nitrogen. Boiling water changes its phase from liquid to gas at 100°C at sea level, and the boiling point can change with atmospheric pressure.
Step-by-step explanation:
The false statement among the ones provided is: The Earth is flat. This is a misconception and scientifically incorrect. The correct statements are: Water boils at 100 degrees Celsius at sea level, oxygen is necessary for combustion, and it is false that humans can breathe underwater without the aid of specialized equipment such as a scuba apparatus.
In relation to water's properties, water is indeed polar, meaning it has a positive and negative end, thereby allowing it to dissolve many substances. It also has the capability to stabilize the temperature of nearby air because of its high heat capacity. Water is essential for life as it is a solvent and medium for chemical reactions in living organisms. However, it is inaccurate to state that water is the most abundant molecule in Earth's atmosphere; that distinction goes to nitrogen.
The boiling point of water is defined as the temperature at which water turns from a liquid to a gas, and this occurs at 100°C at standard atmospheric pressure. At the boiling point, water undergoes a phase change from liquid to vapor (boiling). It is also pertinent to mention that boiling points can vary with changes in atmospheric pressure. For example, on a planet where the atmospheric pressure is lower than Earth's sea level, the boiling point of water would be lower than 100°C.