The organ that is composed of both endocrine and exocrine tissue is the pancreas.

Here's a breakdown:

* Endocrine function: The pancreas produces hormones like insulin and glucagon, which regulate blood sugar levels. These hormones are released directly into the bloodstream.

* Exocrine function: The pancreas produces digestive enzymes like amylase, lipase, and protease, which are released into the small intestine through ducts.

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