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
To construct a coherent and grammatically sound sentence from the provided segments, the initial step involves discerning the logical progression that facilitates correct structure and meaning:
Assembling the segments in sequence, the order QPRS yields the sentence:
"A healthy diet and regular exercise are important habits that help maintain good physical and mental health, especially in today's busy world."
Consequently, the correct arrangement is confirmed as QPRS.