The dinosaurs descended from ______ ancestors.

Options

A. Therapsids
B. Pelycosaurs
C. synapsids
D. Thecodonts

Answer

To answer the question "The dinosaurs descended from ______ ancestors," we need to identify the correct ancestors from the options provided. Here's a step-by-step solution:

### Step 1: Understand the concept of evolution
- Evolution is the process through which species undergo gradual changes over time, leading to the formation of new species. This process is essential for understanding the lineage of organisms, including dinosaurs.

### Step 2: Identify the time period of dinosaurs
- Dinosaurs first appeared during the Triassic period of the Mesozoic era, approximately 252 to 201 million years ago. This is crucial for determining their ancestors.

### Step 3: Determine the ancestors of dinosaurs
- The ancestors of dinosaurs are believed to be a group of reptiles known as the Hekodonts. These were among the early reptiles that existed during the Triassic period.

### Step 4: Evaluate the options given
- The question may provide several options, including Hekodonts, Triopsids, Pelicosaurs, and Cynopsids.
- Triopsids, Pelicosaurs, and Cynopsids are associated with early mammalian ancestors and are not direct ancestors of dinosaurs.

### Step 5: Conclude the correct answer
- Based on the information, the correct answer is that dinosaurs descended from Hekodonts.

### Final Answer:
The dinosaurs descended from **Hekodonts** ancestors.

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