Final answer:
When 4-year-olds and 5-year-olds scramble over jungle gyms, it enhances their cognitive development and encourages physical activity.
Step-by-step explanation:
When 4-year-olds and 5-year-olds scramble over jungle gyms, their cognitive development is enhanced, not discouraged. Physical activity is encouraged, not reduced. While there is a risk of injury, it does not necessarily mean that the risk is reduced. Lastly, socialization skills do not decline; in fact, playing on jungle gyms can promote socialization as children interact and play together.