Final answer:
The term for feeling intellectually alert, emotionally stable, and physically strong is 'balance,' indicative of overall well-being and harmony.
Step-by-step explanation:
The term for feeling intellectually alert, emotionally stable, and physically strong is balance. This reflects a harmonious state where a person's mental, emotional, and physical aspects are in alignment, leading to overall well-being. In the context of developmental theories, like Erikson's and Eysenck's theories, achieving balance can be connected to successfully navigating through life's various stages and mastering challenges such as developing autonomy, feeling competent, achieving integrity, and maintaining emotional stability.