Essential for good health:

Concept:

Good Health:

• Being active and free from physical or mental illness defines one's state of being in good health.

Explanation:

Both A and B:

Environmental cleanliness:

• People's quality of life can be improved by having access to clean air and water, sanitary conditions, green spaces, and safe workplaces.
• This leads to healthier lifestyles, safety from certain diseases, lower mortality and morbidity rates, increased productivity, improved mental health etc. 

Physical hygiene:

• One benefits from practicing good personal hygiene in the following ways:
  • It shields you from illnesses or infections that might impair your immune system.
  • It stops you from infecting your family members and the people you connect with on a daily basis.
  • Over time, it helps maintain the pH levels of your skin, giving it a healthy glow.

Thus, essential for good health are both A and B.