**Core Concept**
The anatomic shape and structure of teeth play a crucial role in their function and occlusion. The cusp angle of a tooth is an essential feature that affects the way it interacts with opposing teeth during mastication.

**Why the Correct Answer is Right**
The ideal cusp angle for anatomic teeth is 20-30 degrees. This angle allows for efficient distribution of forces during occlusion, minimizing the risk of wear and tear on the teeth. A cusp angle within this range enables the tooth to effectively guide food particles towards the occlusal surface, facilitating proper mastication. The 20-30 degree cusp angle also promotes even wear of the opposing teeth, reducing the likelihood of uneven occlusal surfaces.

**Why Each Wrong Option is Incorrect**
* **Option A:** A cusp angle of 0-10 degrees would result in inadequate distribution of forces during occlusion, leading to excessive wear on the teeth.
* **Option B:** A cusp angle of 40-50 degrees would cause the tooth to function as a wedge, leading to uneven occlusal surfaces and potentially causing damage to the opposing teeth.
* **Option C:** A cusp angle of 60-70 degrees would be too sharp, resulting in excessive wear on the opposing teeth and potentially causing discomfort during mastication.

**Clinical Pearl / High-Yield Fact**
A cusp angle of 20-30 degrees is essential for proper occlusion and mastication, and is a key feature of anatomic teeth. This knowledge is crucial for dental and maxillofacial surgeons, as well as general dentists, to ensure proper tooth alignment and function.

**Correct Answer:** C. 20-30 degrees