Answer Explanation

[PASSAGE] "Genetics is the scientific study of heredity, the process by which parents pass certain characteristics, or traits, to their children." This means genetics is the study of how traits are transferred from parents to their offspring. [WHY CORRECT] The first sentence of paragraph 1 directly defines genetics as "the scientific study of heredity, the process by which parents pass certain characteristics, or traits, to their children." Option C, "The passing of characteristics from parents to children," is a direct paraphrase of this definition. [TRAPS] Option A is incorrect because "The structure of the DNA molecule" is discussed later in the paragraph and in paragraph 2 as a component of heredity, not the definition of genetics itself. Option D is incorrect because while genes hold instructions for "building and maintaining an organism," the paragraph explicitly states genetics is the study of how these traits are passed on, not just the development and survival in general. [TIP] When a question asks for a definition or specific detail, always look for explicit statements in the indicated paragraph, especially in introductory sentences. Avoid selecting options that are related concepts but not the direct answer to the question asked.

Why the Other Options Are Incorrect

• Option A (“A) The structure of the DNA molecule”) attaches the right fact to the wrong subject.
• Option B (“B) The chemical composition of cells”) states information not mentioned in the passage.
• Option D (“D) The development and survival of organisms”) distorts a detail that the passage actually gives.

Key Language in Context

The language describing Genetics rewards close reading: notice contrast markers, hedging, and emphasis, since TOEFL detail items hinge on nuance rather than matching keywords.

Skill Takeaway

Match the answer word-for-meaning against the passage rather than the gist.