Final answer:
Children in a preschool exhibit sensitivity to the environment, growth and development, and reproduction as characteristics of living organisms while playing in the park.
Step-by-step explanation:
The three characteristics of living organisms that these children illustrate while playing in the park are sensitivity to the environment, growth and development, and reproduction.
Sensitivity to the environment is demonstrated by the children's ability to respond to stimuli, such as feeling pain when they are hurt and running to their mother for comfort. Growth and development refers to the children's physical and cognitive maturation as they play and learn in the park. Finally, reproduction is exemplified by their potential to have offspring in the future as they grow older.