Correct Answer: B

Rationale: The correct answer is B: Ribosome. Ribosomes, the cellular structures located in the cytoplasm or on the endoplasmic reticulum, are responsible for protein synthesis in the cell. They are the sites where mRNA is translated into proteins, making them essential for the synthesis of proteins in all living cells. The other choices, such as the nucleus (choice
A), endoplasmic reticulum (choice
C), and Golgi apparatus (choice
D), are not directly involved in protein synthesis. The nucleus contains DNA and is responsible for housing the genetic material, the endoplasmic reticulum is involved in protein folding and transport, and the Golgi apparatus is responsible for modifying, sorting, and packaging proteins.

Correct Answer: C

Rationale: The correct answer is C:
To clot blood. Platelets, also known as thrombocytes, have a primary function in blood clotting. They help in the process of coagulation, forming clots to prevent excessive bleeding when injuries occur. Platelets play a crucial role in maintaining the integrity of the circulatory system by sealing off damaged blood vessels and promoting wound healing.

Choices A, B, and D are incorrect because platelets do not carry oxygen, fight infections, or transport nutrients in the blood.

Correct Answer: D

Rationale: The correct answer is D: Producing enzymes. The liver is involved in metabolism by producing enzymes that are essential for regulating various metabolic processes in the body. While the liver does store glucose, secrete bile, and detoxify harmful substances, its primary role in metabolism is producing enzymes that facilitate biochemical reactions necessary for energy production, nutrient breakdown, and waste elimination.

Choices A, B, and C are incorrect because although the liver performs these functions, they are not directly related to its primary role in metabolism, which is producing enzymes.

Correct Answer: C

Rationale: The correct answer is C. The liver's primary function in detoxification is to convert harmful toxins into less harmful substances. This process helps in safeguarding the body from the adverse effects of toxins and is essential for maintaining overall health.

Choices A, B, and D are incorrect because secreting bile, storing glucose, and producing insulin are functions of the liver unrelated to detoxification.

Correct Answer: B

Rationale: The larynx is an essential organ of the respiratory system. It plays a crucial role in producing sound, protecting the trachea from food aspiration, and regulating the airflow to and from the lungs. The brain is part of the nervous system, the urethra is part of the urinary system, and the pancreas is part of the digestive system.
Therefore, they are not directly related to the respiratory system's functions.