The systematic study of population, including its structure, dynamics, and trends, is known as Demography. It focuses on statistics related to population size, density, distribution, and changes over time. Other fields like oceanography focus on marine environments and polygraphy deals with lie detection, not populations.
उत्तर प्रदेश में सर्वाधिक लिंगानुपात वाला जिला है-
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