The case study of Jack and Oskar provides support for which of the following explanations of behavior?

The answer will be Environment has a significant influence on behavior, regardless of gene complement.

Explanation:

Expression of gene can be affected by the influence of the environment. This involve factors related to internal environment, such as various hormones and in case of external environment drug plays an important role. The characteristics of a child as well as the child's temperament and the health as well is always influenced by the environment. Environment also play a great role in case of respiratory health problems,

Hence we can say that environment is related with behavior. They act parallely. Better environment better will be the behavior.