Final answer:
The statement about freedom being a theme of happiness is best understood with reference to psychological well-being, as our natural inclination towards biodiverse environments is key to our mental health and happiness.
Step-by-step explanation:
The statement "Freedom is the basic theme of happiness for all creatures as well as plants" involves understanding how freedom impacts psychological well-being. According to Harvard entomologist E. O. Wilson, our evolutionary history has predisposed us to derive psychological benefits from living in a natural environment. Built environments, conversely, are known to create stressors that can negatively impact our health and well-being.
This body of research supports the idea that exposure to biodiverse, natural landscapes can have regenerative effects on our psychology. Furthermore, there's a moral aspect to consider, as humans have an ethical responsibility to minimize harm to other species. This interrelationship between our well-being and freedom within our environment highlights the essential role freedom plays in the overall happiness of not just humans, but all living beings.