Which structure in the skin is responsible for producing oil that keeps the skin and hair moisturized?

Correct Answer: B

Rationale: The correct answer is B: Sebaceous gland. Sebaceous glands are responsible for producing oil (sebum) that keeps the skin and hair moisturized. Sudoriferous glands produce sweat, not oil, and are involved in temperature regulation. Hair follicles are responsible for hair growth and do not produce oil directly. Melanocytes are cells responsible for producing melanin, the pigment that gives skin its color, and are not involved in oil production.

Correct Answer: B

Rationale: The correct answer is B: 'To filter waste from the blood.' The lymphatic system is responsible for draining excess fluid from tissues, absorbing fats from the digestive system, and filtering out harmful substances and waste products from the blood. It also plays a crucial role in the body's immune defense by transporting white blood cells and antibodies to fight off infections. Choices A, C, and D are incorrect because transporting oxygen, producing red blood cells, and regulating body temperature are functions performed by other systems in the body, such as the respiratory system, bone marrow, and thermoregulatory mechanisms, respectively.

Correct Answer: B

Rationale: The medulla oblongata is located at the base of the brainstem and is responsible for controlling vital involuntary functions such as breathing, heart rate, and blood pressure. The cerebrum, although the largest part of the brain, is primarily responsible for higher brain functions like thinking and voluntary muscle movements. The cerebellum is involved in coordination, balance, and muscle control. The thalamus acts as a relay station for sensory information but is not directly responsible for regulating involuntary functions like breathing and heart rate. Therefore, the correct answer is the medulla oblongata.

Correct Answer: B

Rationale: White blood cells play a crucial role in the immune system by fighting infection and protecting the body from foreign invaders. Choice A, 'To transport oxygen,' is incorrect because red blood cells are responsible for transporting oxygen. Choice C, 'To carry oxygen,' is also inaccurate for the same reason. Choice D, 'To produce antibodies,' while related to the immune system, is not the primary function of white blood cells, as their main role is to directly combat infections.

Correct Answer: B

Rationale: Lymph nodes are responsible for filtering lymph and supporting the immune system. They contain immune cells that trap and destroy pathogens, making them crucial in immune response. The other choices, kidneys, pancreas, and liver, do not play a direct role in filtering lymph or supporting the immune system. The kidneys filter blood to remove waste and regulate electrolytes, the pancreas is involved in digestion and blood sugar regulation, and the liver is primarily responsible for detoxification and metabolism.