Here are complete sentences based on the given questions:

1. **What is necessary for maintaining good physical and mental health?**
Maintaining good physical and mental health requires adopting healthy habits, such as eating a balanced diet, staying active, managing stress, and getting enough sleep.

2. **What are some simple lifestyle changes that can improve overall well-being?**
Some simple lifestyle changes that can improve overall well-being include eating nutritious foods, exercising regularly, getting sufficient sleep, and practicing stress-reduction techniques.

3. **What does regular physical activity help us with?**
Regular physical activity helps us strengthen our muscles and bones, improve heart health, enhance mood, and reduce the risk of chronic diseases.

4. **Why is getting enough sleep good for maintaining good health?**
Getting enough sleep is essential for maintaining good health because it allows the body to rest, recover, and rejuvenate, ultimately preventing fatigue and improving overall functioning.

5. **Can healthy habits help us prevent health problems and live longer in the future?**
Yes, adopting healthy habits can help prevent health problems and increase longevity by promoting better physical and mental health throughout our lives.

6. **Acne/cause/black and white pimples/the face.**
Acne is caused by a combination of factors, including clogged pores, excess oil production, and bacteria, which result in black and white pimples on the face.