Demography is the scientific study of what aspect of human population size, structure, distribution, and growth?

Introduction / Context:
Demography is a core concept in social science, economics, and public policy. It focuses on understanding how human populations change over time and space. This question tests whether you know that demography is not about individual people or animals, but about human population size, structure, distribution, and growth patterns at a group level.

Given Data / Assumptions:
- The term being tested is demography.
- The context is the scientific study of populations, especially human populations.
- We assume the standard social science definition used in population studies and census work.

Concept / Approach:
Demography is defined as the scientific study of human populations, primarily with respect to size, composition, distribution, and the processes that change these characteristics, such as births, deaths, migration, and aging. It uses statistical methods to analyze data that describe populations and how they evolve over time. The concept is not restricted to one narrow aspect like birth rate or death rate, but covers the broader patterns of population dynamics.

Step-by-Step Solution:
Step 1: Recall that demography is related to population, not the environment or individual psychology. Step 2: Note that it focuses on characteristics such as size, age structure, sex ratio, and spatial distribution. Step 3: It also involves studying processes like fertility, mortality, and migration that cause populations to grow or shrink. Step 4: Among the options, only the choice that mentions human population size, structure, distribution, and growth patterns matches this broad, accepted definition.

Verification / Alternative check:
A quick way to verify is to think of how demographers work in censuses and surveys. They analyze data on how many people live in a region, their ages, education, occupations, and how these variables change over time. This confirms that demography is about population characteristics and trends, not about individual plants, animals, or landforms.

Why Other Options Are Wrong:
Option B: Individual psychological traits of human beings are studied in psychology, not demography.
Option C: Physical features and landforms of the Earth's surface fall under geology or physical geography, not demography.
Option D: Plants, animals, and other nonhuman living organisms are studied in biology or ecology, not under demography, which is specifically about human populations.

Common Pitfalls:
A common mistake is to think that demography only covers birth and death rates or only population growth. In reality, it includes structure (age and sex composition), distribution (where people live), and other demographic processes. Another pitfall is confusing demography with ecology, which studies relationships between organisms and their environments.

Final Answer:
The correct answer is human population size, structure, distribution, and growth patterns because demography is defined as the scientific study of these aspects of human populations.