In the following question, out of the four alternatives, choose the one which can be substituted as a single word for the description: "The study of birds is known as ______."

Introduction / Context:
This question checks your knowledge of subject specific one-word substitutes used in science. The description is "The study of birds is known as ..." Exams often test such branch names, because they are basic scientific vocabulary that every educated person is expected to know.

Given Data / Assumptions:

• We need the name of the branch of science that studies birds.
• Options include Ornithology, Zoology, Biology, Anatomy, and Entomology.
• The question is asking for a precise term, not a general category like "science".
• We assume standard English usage in scientific classification.

Concept / Approach:
"Ornithology" is the scientific study of birds. The word comes from Greek "ornis" meaning bird and "logia" meaning study. "Zoology" is the broader study of animals, "biology" is the study of living organisms in general, "anatomy" focuses on internal structure of organisms, and "entomology" is the study of insects. So the narrow, exact term for bird study is "Ornithology".

Step-by-Step Solution:
Step 1: Identify the central word in the description: birds.Step 2: Recall the exact scientific branch name for bird study.Step 3: Remember that "ornithology" is the study of birds.Step 4: Compare with other options which are wider fields or focus on other creatures.Step 5: Select "Ornithology" as it directly fits the requirement.

Verification / Alternative check:
Use the word in context: "He is doing research in ornithology and specialises in migratory birds." This clearly tells us that ornithology is about birds. If we used "entomology" in the same sentence, it would indicate insect research, which is wrong. If we used "zoology", we would lose the specific focus on birds and refer instead to all animals. Therefore, ornithology is the most accurate one-word substitute.

Why Other Options Are Wrong:

• Zoology: The scientific study of animals in general, including mammals, birds, reptiles, and more, not limited to birds.
• Biology: The broad study of all living organisms, plants and animals, microorganisms and more.
• Anatomy: The branch of science that deals with the structure of organisms and their parts, such as bones and organs.
• Entomology: The scientific study of insects, not birds.

Common Pitfalls:
Students sometimes choose "zoology" because they know that birds are animals. However, the question explicitly asks for the name of the study of birds, not animals in general. Whenever you see a very specific description in the question, your answer should match that level of specificity, not jump to a larger category.

Final Answer:
The correct one-word substitute for the study of birds is Ornithology.