The environmental lapse rate refers to the rate at which temperature changes as you move up or down in the atmosphere. In general, the temperature decreases as you go higher in the atmosphere, and this rate of decrease is called the environmental lapse rate.
Out of the options provided, the correct answer is "0.60C for every 100 m ascent". This means that for every 100 meters increase in altitude, the temperature in the atmosphere decreases by 0.6 degrees Celsius. It's important to note that this is just an average rate, and the actual rate can vary depending on a number of factors such as time of day, location, and weather conditions.
Understanding the environmental lapse rate is important in meteorology and climatology because it can help scientists and forecasters predict how temperature will change with altitude, and how this will affect weather patterns and climate conditions.