Which of the following is included in the endomembrane system?

In which of the following are cisternae found?

Rough Endoplasmic Reticulum $(RER)$ $= ..........P.............$
Smooth Endoplasmic Reticulum $(SER)$ $= ......Q...........$
What substances do the above Endoplasmic Reticula synthesize/secrete respectively?

Which of the following statements is incorrect about the Golgi apparatus?

$A$ cell organelle '$X$' is divided into two types on the basis of a cell organelle '$Y$',which helps in protein synthesis. Identify '$X$' and '$Y$' respectively.

Which organelle of the cell is responsible for the synthesis of steroids?