Final answer:
Exocrine glands secrete their products through ducts that lead outside the gland, not into the blood.
Step-by-step explanation:
Exocrine glands secrete their products through ducts that lead outside the gland, not into the blood. Examples of exocrine glands are sweat glands and salivary glands. Unlike endocrine glands, exocrine glands do not secrete hormones into the blood. Therefore, the correct answer is option 4) secrete hormones into an attached duct.