Pancreatic cells, which secrete a large amount of digestive enzymes, are labeled with radioactive leucine and then chased for several hours withnonradioactive leucine. Photographic emulsions are prepared at different times during the chase. Where would the black spots appear on an emulsionprepared 3 hours after the pulse?
A- Rough ER
B- Secretory vesicles
C- Golgi apparatus
D- Exterior of the cell