What was the first organ of the internal digestive system?Group of answer choicesEsophagusLiverStomachSmall intestine

To determine the first organ of the internal digestive system, we can analyze the digestive system's structure and function.

1. Understanding Digestive System Function: The digestive system is responsible for breaking down food, absorbing nutrients, and expelling waste. It begins with the mouth and continues through various organs.

2. Sequential Digestion Process:

   • Mouth: Food is initially ingested and mechanically broken down by teeth, and saliva begins the chemical process.
   • Esophagus: After chewing, food travels down the esophagus to reach the stomach.
   • Stomach: Here, food is mixed with gastric juices for further breakdown.
   • Small Intestine: This is where most nutrient absorption occurs.

3. Identifying the First Organ: Given this understanding, while the mouth technically starts the digestive process, if we focus strictly on internal organs, the esophagus is the first organ that carries food from the mouth to the stomach.

Final Answer

The first organ of the internal digestive system is the Esophagus.