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 jejunum is the correct answer. It is the primary site of nutrient absorption in the small intestine. The duodenum mainly facilitates digestion, the ileum is responsible for further absorption, while the cecum is part of the large intestine and not involved in nutrient absorption.

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: D

Rationale: The correct answer is the cardiovascular system (Option
D). The cardiovascular system is responsible for transporting oxygenated blood from the lungs, where oxygen is absorbed, to various tissues and organs in the body, including the spleen. The immune system (Option
A) is responsible for defending the body against infections and diseases. The endocrine system (Option
B) regulates hormones and their effects on the body. The respiratory system (Option
C) is responsible for the exchange of gases, such as oxygen and carbon dioxide, in the lungs.

Correct Answer: B

Rationale: The correct answer is B: "
To fight infection." White blood cells are primarily responsible for fighting infections and foreign invaders in the body, making them a critical component of the immune system.
Choice A, "
To carry oxygen," is incorrect as red blood cells are responsible for oxygen transport.
Choice C, "
To transport nutrients," is incorrect as this function is mainly attributed to blood plasma and other specialized cells.
Choice D, "
To transport waste," is also incorrect as waste removal is primarily handled by the kidneys and the lymphatic system, not white blood cells.