Final answer:
Cooperative play is the activity that escalates during preschool years, characterized by significant social development, including the sharing, collaboration, and role playing. Children's play evolves by ages six to ten, as they enjoy mixed-gender group activities and demonstrate a growing preference for teamwork and cooperative activities.
Step-by-step explanation:
The activity that dramatically increases during the preschool years and involves turn-taking, conversations, social games and routines, and physical play is (b) Cooperative play. This type of play signifies children's increased ability to collaborate, share, and assume roles in a group setting. During the cooperative play stage, children can participate in activities that require understanding multiple roles simultaneously and how they interact, such as the varied responsibilities in a restaurant.
As children grow, particularly from ages six to ten, they transition from playing with same-gender friends to engaging in mixed-gender group activities. During this period, children exhibit a natural tendency towards cooperation and sharing, though they may also experience occasional jealousy. They can enjoy team sports, like Little League Baseball, or become part of scouts and other peer groups.