Answer:
The smooth endoplasmic reticulum
Step-by-step explanation:
Smooth ER (SER) can have both plants or animals and it has a couple of functions such as synthesis of lipids and hormones, regulates calcium ions and others.
It can detoxicate harmful products such as drugs and poisons in this case and that's why this organelle is missing. It is a very important one. Another type of ER is rough ER.