Answer:
Protein
Step-by-step explanation
Ribosome and Rough E.R are organelles in the cell.
E.R are extensive membranes (which are continuous with the nuclear membrane) that exist as flattened compartment in the cytoplasm.These compartment form sacs in the cytoplasm. The sacs are interconnected with one another to form a complete system called the reticulum.
Based on structure two types of E.R exists -the Smooth E.R and the Rough Endoplasmic reticulum.The later is called rough because of Ribosomes attached to its outer membrane. the smooth lacks ribosomes attachment on its outer membrane. Ribosomes are the site of Protein synthesis in the cell.
They are small in number and are made up of RNA and protein.Generally the protein synthesised in the Ribosomes,are moved into the sacs in the R.E.R,where they are modified.They are eventually budded off in vesicles which form the Golgi bodies