What is NOT true about Shigella?

Correct Answer: B

Rationale: The correct answer is B because Shigella is a non-motile species and does not possess a flagellum. Shigella relies on non-flagellar mechanisms for its movement within host cells. Choice A is true as Shigella causes bloody diarrhea. Choice C is also true as Shigella exploits M cells to infect the host. Choice D is true as Shigella can move from cell to cell using actin comets. In summary, choice B is incorrect because Shigella does not have a flagellum, while choices A, C, and D are all true characteristics of Shigella.

Correct Answer: C

Rationale: Rationale: Afferent lymphatic vessels transport lymph containing antigens from tissues to lymph nodes (LN). Option C is correct because afferent lymphatics do not transport antigens directly from the blood to LN. Other choices are incorrect because afferent lymphatics enter LN at multiple sites (B), transport antigens from tissues to LN (A), and connect tissues to secondary lymphoid organs (D).

Correct Answer: A

Rationale: The correct answer is A: plants response to stimulation. Tropism refers to the growth or movement of an organism in response to a stimulus. Plants exhibit tropisms such as phototropism (response to light) and geotropism (response to gravity). This choice accurately defines the phenomenon. Choice B is incorrect because reducing lateral branching is not a defining characteristic of tropism. Choice C is incorrect because the length of day and night does not directly relate to tropism. Choice D is incorrect because not all options listed are characteristics of tropism.

Correct Answer: D

Rationale: The correct answer is D because neurons are specialized cells that carry signals, making them the functional units of the nervous system. Neurons consist of a cell body, dendrites, and axons, fulfilling the criteria mentioned in options A, B, and C. Therefore, option D encompasses all the essential characteristics of neurons, making it the correct choice. Options A, B, and C individually do not fully capture the comprehensive nature of neurons, as they only cover specific aspects of what neurons are, whereas option D encompasses all the correct statements regarding neurons.

Correct Answer: C

Rationale: The correct answer is C: Anemia. Anemia is the medical term for an abnormal decrease in red blood cells. Red blood cells are responsible for carrying oxygen throughout the body, and a decrease in their numbers can lead to symptoms like fatigue, weakness, and paleness. Rationale: 1. Leukopenia (A) refers to a decrease in white blood cells, not red blood cells. 2. Thrombocytopenia (B) is a decrease in platelets, which are involved in blood clotting, not red blood cells. 3. Hemolysis (D) is the breakdown of red blood cells, not a decrease in their numbers. In summary, anemia is the correct answer as it specifically describes the condition of low red blood cell count, while the other choices are related to decreases in different components of blood.