**Core Concept**
Saturated fatty acids are a type of dietary fat characterized by the absence of double bonds between carbon atoms. This chemical structure makes them more stable and solid at room temperature, which is why they are often found in animal products and tropical oils.

**Why the Correct Answer is Right**
Saturated fatty acids are predominantly found in animal products such as butter, lard, and beef tallow. They are also present in significant amounts in tropical oils like coconut oil and palm oil. The high saturated fat content in these products contributes to their characteristic solid or semi-solid texture at room temperature.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not specify the correct source of saturated fatty acids. While some plant-based oils may contain saturated fats, they are not the primary source.
**Option B:** This option is incorrect because it is too vague and does not accurately describe the primary sources of saturated fatty acids.
**Option C:** This option is incorrect because it is a type of unsaturated fatty acid, which is found in high quantities in certain plant-based oils like olive oil and nuts.

**Clinical Pearl / High-Yield Fact**
Saturated fatty acids are often associated with increased cholesterol levels and cardiovascular disease risk, making them a topic of interest in clinical nutrition and preventive medicine.

**Correct Answer:** D. Dietary sources of saturated fatty acids include animal products and tropical oils.