The endocrine system is comprised of endocrine glands that secrete hormones directly into the blood rather than through ducts. Glands are organs in the bodies of humans or animals that secrete chemicals for bodily use or to go into the environment. Ducts are tubular canals in the body that carry secretions from glands.
C. They are not enclosed by a membrane.
D is incorrect because Ribosomes do not contain DNA, the nucleolus does.
B is also incorrect because they aren't located outside the cell, they're in the cell, on the endoplasmic reticulum.
Hoped this helped :)
The first answer is the correct one
