In human genetics and social biology, eugenics is the study of which of the following?

Introduction / Context:
Eugenics is a term that appears in discussions of human genetics, history, and social policy. It refers to a controversial movement and field of study that aimed to influence the genetic qualities of human populations. The question asks you to identify the correct definition of eugenics from several options that mention races, plants, and specific groups of people. Understanding the precise meaning of the term is important for general knowledge as well as for ethical debates about genetics and society.

Given Data / Assumptions:
- The question is specifically about eugenics, not about general genetics or anthropology.
- Eugenics historically focused on human populations and their hereditary traits.
- The options include improvement or description of racial qualities, study of human races, plant genetics, and particular human groups.
- Only one option captures the core idea of attempting to modify or improve hereditary characteristics in future human generations.

Concept / Approach:
Eugenics combines ideas from genetics and social planning. Its goal, as originally stated by its supporters, was to improve the genetic quality of the human population by encouraging reproduction of individuals with traits considered desirable and discouraging reproduction of those with traits considered undesirable. This involves both physical and mental characteristics. By contrast, anthropology may study different races, botany studies plant genetics, and ethnology may focus on specific ethnic groups. Therefore, the correct answer must explicitly refer to improving racial or hereditary qualities of future human generations, not simply describing or classifying them.

Step-by-Step Solution:
Step 1: Read the keyword eugenics and recall that it relates to genetics and the idea of improving human heredity. Step 2: Evaluate option A, which states improve the racial qualities of future generations either physically or mentally, matching the core meaning of eugenics. Step 3: Evaluate option B, different races of mankind, which describes a descriptive study of races rather than efforts to change hereditary qualities. Step 4: Evaluate option C, genetics of plants, which belongs to botany and has no relation to the specific term eugenics. Step 5: Evaluate option D, people of European origin, which is a narrow ethnic focus and does not capture the general concept of eugenics. Step 6: Evaluate option E, evolutionary history of primates, which belongs to evolutionary biology and paleoanthropology, not specifically to eugenics. Step 7: Confirm that option A is the only one that accurately reflects the definition of eugenics.

Verification / Alternative check:
As an additional check, you can break down the word: eu means good or well, and genics relates to birth or origin. This literally suggests good birth or improving the stock. Historical accounts of eugenics describe policies such as selective breeding, marriage laws, and forced sterilizations aimed at altering the genetic composition of populations. These practices were justified by claims of improving physical and mental traits in future generations, which matches the wording of option A. The other options either describe different scientific fields or focus on specific groups without the improvement aspect.

Why Other Options Are Wrong:
Different races of mankind, option B, refers to the study or classification of races, which is more closely related to anthropology and ethnology, not specifically to eugenics.
Genetics of plants, option C, falls within plant breeding and botany, and although plant breeding can be similar in concept, eugenics by definition focuses on human populations.
People of European origin, option D, is only one particular group and does not describe the general aim or scope of eugenics as a field.
Evolutionary history of primates, option E, is studied under evolutionary biology and paleoanthropology and does not include the directed improvement goal that defines eugenics.

Common Pitfalls:
Some learners may confuse eugenics with general racial studies and mistakenly choose an option that focuses only on describing human races. Others may be misled by the similarity between plant breeding and human genetic control and think the term applies mostly to plants. It is important to remember that eugenics specifically refers to attempts to improve human hereditary traits through controlled reproduction, which carries significant ethical concerns when applied in society.

Final Answer:
Eugenics is the study and practice aimed to improve the racial qualities of future generations either physically or mentally by influencing human reproduction and hereditary traits.