Concept:Endocrine glands are ductless glands that release hormones directly into the bloodstream.
Explanation:Endocrine system properties include the secretion of hormones.
Hormones are transported by blood to their target organs.
Hormones have specific effects on their target organs.
However, releasing secretion into ducts is a property of exocrine glands, not endocrine glands.
Therefore, the option that is not a property of the endocrine system is the release of secretion into ducts.
Answer:D. release of secretion into ducts