What two activities are part of a client's warm-up?

The correct choice highlighting flexibility and cardio as parts of a warm-up is grounded in the understanding of effective exercise preparation. During a warm-up, the primary aim is to gradually increase the heart rate and circulation, which is accomplished through cardiovascular activities. This can include light jogging, dynamic stretches, or other movements that elevate the body temperature.

Additionally, flexibility work is crucial in a warm-up as it prepares the muscles and joints for more intense activity, reducing the risk of injury. Stretching helps improve the range of motion and encourages blood flow to the muscles, further enhancing readiness for subsequent exercises.

In contrast, other options involve components that may not align fully with the objectives of a warm-up. While strength, balance, core, power, aerobic, and anaerobic activities are important aspects of a fitness program, they typically pertain to specific training goals or phases rather than serving the foundational purpose of a warm-up session. Therefore, flexibility and cardio are the two activities most fitting for a warm-up routine, ensuring that the body is adequately prepared for more vigorous exercise.