Answer:
The correct statment would be: "the hormons of the endocrine system exert their action by lock and key mechanism."
Step-by-step explanation:
The endoncrine system is responsable of the release of hormons under certain conditions, and in different organs, they go trough the bloodstream. The lock and key mechanism is explained as how the receptors block or release hormonos or instead they don´t. The endocrine system is responsable for the reproductive system, and regulates metabolic processes.