Arrange the sentences logically:
1. He was terrified by the noise.
2. Suddenly, a loud sound was heard.
3. Everyone looked towards the door.
4. The children ran out of the room.
Rearrange the following parts to form a meaningful and grammatically correct sentence:
P. a healthy diet and regular exercise
Q. are important habits
R. that help maintain good physical and mental health
S. especially in today's busy world