Demography is the study of the size, composition, growth (or shrinkage), and distribution of human populations.

• A. The study of the size, composition, growth (or shrinkage), and distribution of human populations.
• B. The science of human behavior
• C. The study of cultures
• D. The study of economic systems

Answer: (A)

Demography looks at population-wide measures: how many people there are, who they are (age, sex, ethnicity, etc.), how the population grows or shrinks, and where people live. It relies on data such as birth rates, death rates, and migration to understand changes over time and space, and to inform planning for services like schools and healthcare. This focus on population size, composition, growth, and distribution distinguishes it from other fields: the science of human behavior examines how people act and think, the study of cultures explores shared beliefs and practices, and the study of economic systems analyzes how economies organize production and distribution. So the description that matches these population-focused questions is the correct one.