1. The problem asks to identify the lower limit of the fifth class in a grouped frequency distribution of social interactions. 2. The classes are given as intervals: 20-24, 25-29, 30-34, 35-39, 40-44, 45-49, 50-54, 55-59, 60-64, 65-69. 3. Each class interval represents a range of social interactions, and the lower limit is the smallest number in that interval. 4. To find the lower limit of the fifth class, count the classes in order: - 1st class: 20-24 - 2nd class: 25-29 - 3rd class: 30-34 - 4th class: 35-39 - 5th class: 40-44 5. The lower limit of the fifth class is the smallest number in the interval 40-44, which is $40$. 6. Therefore, the lower limit of the fifth class is $40$. Final answer: $40$