Final answer:
The liver detoxifies substances like barbiturates and alcohols mainly through the smooth endoplasmic reticulum, which metabolizes these toxins into less harmful products for excretion.
Step-by-step explanation:
The liver utilizes various mechanisms for the detoxification of substances such as barbiturates & alcohols. However, when it comes to the detoxification of sedatives like barbiturates and alcohols such as ethyl alcohol, the primary organ responsible is the liver, and the specific organelle involved is the smooth endoplasmic reticulum (SER). The SER works by converting these toxic substances into less harmful products through reactions that involve a variety of enzymes, ultimately making them ready for excretion. While peroxisomes also play a role in detoxification, particularly with alcohol, the SER is the main site for metabolizing a wide range of drugs and toxins. Therefore, the correct answer to the question "The liver detoxifies sedatives such as barbiturates & alcohols such as ethyl alcohol using:" is (C) Smooth endoplasmic reticulum.