The number indicating that the population is growing at its fastest rate is 2. Hence the correct option is 2.
In the given graph representing population changes over time, the point identified by number 2 corresponds to the period during which the population is experiencing the fastest rate of growth. The steep slope at this point indicates a rapid increase in the number of individuals within the population over a short time span.
This phase suggests favorable conditions, such as abundant resources or reduced environmental constraints, leading to a surge in population size. The steep incline in the graph at point 2 signifies a period of robust population growth, highlighting a phase where the birth rate surpasses the death rate. Analyzing such points on the graph is essential for understanding population dynamics and the factors influencing growth patterns over time. Hence the correct option is 2.