The only human system that is derived from all the three germ layers is

The correct option is Digestive system.

During embryonic development, the process of gastrulation establishes three primary germ layers: the ectoderm, the mesoderm, and the endoderm. These layers give rise to all the tissues and organs in the human body. While most organ systems develop from one or two of these germ layers, the digestive system is unique because it receives contributions from all three germ layers:

1. Endoderm:
The endoderm forms the epithelial lining of the gastrointestinal tract (from the pharynx to the upper part of the anal canal), as well as the parenchyma of the associated glands such as the liver, gallbladder, and pancreas.

2. Mesoderm:
The mesoderm forms the surrounding connective tissue, smooth muscle layers of the gut wall, and the peritoneal coverings (visceral peritoneum).

3. Ectoderm:
The ectoderm forms the epithelial lining of the extreme ends of the digestive tract, namely the mouth (stomodeum) and the lower part of the anal canal (proctodeum).

Thus, because it integrates tissues derived from the ectoderm, mesoderm, and endoderm, the digestive system is the only human system derived from all three germ layers.