The
is a network of canals and sacs made of cell membrane. there are
two types of this structure: the
and

The endoplasmic reticulum  is a network of canals and sacs made of cell membrane. There are two types of this structure: the Rough endoplasmic reticulum and the smooth endoplasmic reticulum.

Explanation:

Endoplasmic reticulum is an irregular network of double membrane distributed over the entire cytoplasm of the cell.It establishes  connection between the cell membrane and the nuclear membrane.Endoplasmic reticulum is classified into two types depending on the presence and absence of ribosome on its surface.If ribosome are present on it surface then it is called rough endoplasmic reticulum and if ribosomes are absent on its surface then it is called smooth endoplasmic reticulum.Endoplasmic reticulum functions producing, processing and transporting biochemical compounds like protein and lipids. It also forms the supporting framework of the cell.