The correct statement is option 2: "The boiling point of water depends on atmospheric pressure."

Option 1 is incorrect because the boiling point of water is not always 100°C. The boiling point of water can vary depending on the conditions.

Option 3 is incorrect because the material of the container in which water is boiled does not affect its boiling point. The boiling point of water remains the same regardless of the container material.

Option 4 is incorrect because the source of heat does not directly affect the boiling point of water. The boiling point of water is primarily determined by atmospheric pressure.

At sea level, water boils at 100°C at normal atmospheric pressure. However, as we go higher in altitude where the atmospheric pressure is lower, the boiling point of water decreases. This means that at higher altitudes, water boils at a lower temperature.

It is important to note that atmospheric pressure is the primary factor influencing the boiling point of water. Other factors such as impurities in the water or additional atmospheric conditions may have a secondary effect but are not as significant as atmospheric pressure.