List-I ( Ions ) | List-II ( No. of unpaired electrons ) | ||
| A | Zn$^{2+}$ | (I) | 0 |
| B | Cu$^{2+}$ | (II) | 4 |
| C | Ni$^{2+}$ | (III) | 1 |
| D | Fe$^{2+}$ | (IV) | 2 |
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