Correct Answer: D

Rationale: The correct answer is D, 'All of the above.' The large intestine performs various functions, including the absorption of water, production of vitamin K, and production of some B vitamins. Water absorption is a crucial function of the large intestine, helping to concentrate waste material into feces. Additionally, the large intestine hosts beneficial bacteria that produce vitamin K and some B vitamins, which are absorbed into the body. Choices A, B, and C individually represent specific functions of the large intestine, while choice D correctly encompasses all these functions, making it the most comprehensive and accurate answer.

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: A

Rationale: The correct answer is A: Ectoderm. The nervous system develops from the ectoderm, which is the outermost of the three germ layers. The ectoderm gives rise to structures such as the skin, hair, nails, and the entire nervous system. Choices B, C, and D are incorrect because the endoderm gives rise to the lining of the gut and associated organs, the gastroderm is not a recognized germ layer, and the mesoderm forms structures like muscles, bones, blood, and the circulatory system, but not the nervous system.

Correct Answer: B

Rationale: The correct answer is B: 'To filter waste from the blood.' The kidneys are vital organs responsible for filtering waste products from the blood, regulating fluid and electrolyte balance, and producing urine. Choice A is incorrect because the production of digestive enzymes primarily occurs in the pancreas and salivary glands. Choice C is incorrect as the production of white blood cells mainly takes place in the bone marrow and lymphatic system. Choice D is incorrect as the production of red blood cells occurs in the bone marrow.

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.