Q: Fact 1: Ribosomes are sites where proteins are made. Fact 2: Endoplasmic reticulum are membranes attached to ribosomes. Given the two facts above, what are membranes attached to sites where proteins are made?

Select from: (1). the body's largest organ (2). Veins and arteries. (3). epidermis and dermis (4). layers of fat (5). cell walls (6). cell membranes (7). endoplasmic reticulum (8). brain cells
The answer is:
(7).