Final answer:
The most likely pathway taken by a newly synthesized protein that will be secreted by a cell is ER - Golgi - vesicles that fuse with plasma membrane. Proteins are synthesized in the rough endoplasmic reticulum (ER) and then transported to the Golgi apparatus by vesicles. In the Golgi, the proteins are modified and sorted before being packaged into secretory vesicles that fuse with the plasma membrane and release their contents outside the cell.
Step-by-step explanation:
The most likely pathway taken by a newly synthesized protein that will be secreted by a cell is ER - Golgi - vesicles that fuse with plasma membrane (option B). Proteins are synthesized in the rough endoplasmic reticulum (ER) and then transported to the Golgi apparatus by vesicles. In the Golgi, the proteins are modified and sorted before being packaged into secretory vesicles that fuse with the plasma membrane and release their contents outside the cell.