Vertebrate eyes are Single-lens eyes with

Correct Answer: D

Rationale: The correct answer is D because vertebrate eyes have single-lens eyes where light is focused by the curved cornea and lens (A), and changing the shape of the lens allows for focusing at different distances (B). Additionally, photoreceptor cells in the retina detect light (C). Therefore, all of the above statements are true, making D the correct choice. Choice A is incorrect because it does not encompass the entire process of vision in vertebrate eyes, missing the role of changing the lens shape. Choice B is incorrect as it only addresses the lens shape without mentioning the role of the cornea in focusing light. Choice C is incorrect as it only focuses on the function of photoreceptor cells in the retina without considering the lens and cornea's role in focusing light.

Correct Answer: B

Rationale: The correct answer is B: Producing hormones. The immune system's main functions are to protect the body from foreign substances and repair damaged tissues. Producing hormones is not a direct function of the immune system. Hormone production is primarily regulated by the endocrine system, not the immune system. Therefore, option B is not a function of the immune system. Options A and C are incorrect as protecting the body from foreign substances and repairing damaged tissues are essential roles of the immune system. Option D is incorrect because not all functions listed are actually performed by the immune system.

Correct Answer: C

Rationale: The correct answer is C: Aplastic anemia. Aplastic anemia is a condition where the bone marrow doesn't produce enough blood cells, including red blood cells. Iron deficiency anemia (A) is caused by a lack of iron in the body, not a deficiency in red blood cell production. Sickle cell anemia (B) is a genetic disorder affecting the shape of red blood cells, not the production. Pernicious anemia (D) is caused by a lack of vitamin B12, which leads to a deficiency in red blood cell production, but it is not the medical term specifically used for this condition.

Correct Answer: B

Rationale: Step-by-step rationale: 1. Lysozyme is an enzyme that destroys bacterial cell walls. 2. This action acts as a preformed chemical barrier against pathogens. 3. Mucus (choice A) is a physical barrier, not a preformed chemical one. 4. Tight junctions (choice C) and cilia (choice D) are structural components, not chemical barriers. Summary: - Choice B, Lysozyme, is correct as it actively targets and destroys pathogens. - Choices A, C, and D are incorrect as they do not directly function as preformed chemical barriers.

Correct Answer: C

Rationale: The correct answer is C: Mast cells: acute phase response. Mast cells are actually involved in allergic responses, not the acute phase response of the immune system. The acute phase response is primarily mediated by cytokines and acute-phase proteins. Interferons protect against viral infections, ROS help kill pathogens inside cells, and selectins aid in leukocyte extravasation during inflammation.