Answer:
They are elaborate network of channels running through the cytoplasm. There are two types of endoplasmic reticulum. They are; Rough and smooth endoplasmic reticulum. Rough endoplasmic reticulum are rough because of the presence of ribosomes. Smooth endoplasmic reticulum are smooth because they dont have ribosomes.
meaning:an extensive intracellular membrane system whose functions include synthesis and transport of lipids and, in regions where ribosomes are attached, of proteins
