LIST I | LIST II | ||
| A | Controlling TV channels through remote | I | Circuit switching |
| B | Moving elevators up/down | II | Simplex communication |
| C | Communication between two computers | III | Half-duplex communication |
| D | Communication through telephone call | IV | Full-duplex communication |
Column-I has statements made by Shanthala; and, Column-II has responses given by Kanishk.

Identify the part of the sentence that contains a grammatical error:
Each of the boys have submitted their assignment on time.
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