Final answer:
Vesicles from the ER enter the Golgi apparatus at the cis Golgi network, which is the receiving area for substances that are then modified as they pass through the Golgi.
Step-by-step explanation:
The cis Golgi network area is known as the receiving side of the Golgi apparatus, where transport vesicles from the ER fuse with it and release their contents into the Golgi's lumen. As substances travel through the Golgi apparatus, they are modified through processes such as glycosylation and phosphorylation, which can determine their final destinations.