Answer:
d.optimal level of arousal.
Explanation:
Optimal arousal is a psychological construct referring to a level of mental stimulation at which physical performance, learning, or temporary feelings of wellbeing are maximised .
Reference:
Smith, S. 1990 Dictionary of Concepts in Recreation and Leisure Studies. Westport: Greenwood.
Answer:
The study of Economics can help you know this right away. Economics is very vital for the businessman or businesswoman in the sense that a thorough understanding in Economics can help him or her to minimize the cost of production and make more profit at the end of the day. Economics is very important for the consumer.
If you're talking about branches, then it's the legislative branch.