Tropism is a phenomenon by which

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: 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.

Correct Answer: A

Rationale: The correct answer is A: He was the first to observe microorganisms. Van Leeuwenhoek's important contribution to microbiology was his discovery of microorganisms using his own handcrafted microscopes. This observation revolutionized the field by providing the first direct evidence of the existence of microorganisms. Choice B is incorrect because Leeuwenhoek's observations actually supported the idea of spontaneous generation. Choice C is incorrect because he did not link microorganisms to diseases. Choice D is incorrect because the process of fermentation was described by others before Leeuwenhoek.

Correct Answer: D

Rationale: The correct answer is D - All of the above. Lectin receptors recognize microbial carbohydrates, are expressed on phagocytes, and can be classified as pattern recognition receptors. Lectins are proteins that bind specifically to certain carbohydrates, allowing them to recognize and interact with pathogens. Phagocytes express lectin receptors to help identify and engulf pathogens. Additionally, lectin receptors are considered pattern recognition receptors because they recognize specific patterns or structures commonly found on pathogens. Therefore, all three statements are true, making option D the correct answer.

Correct Answer: B

Rationale: The correct answer is B: Increased concentration of C-reactive protein. This is because C-reactive protein is a well-established clinical indicator of inflammation, produced by the liver in response to inflammation. Choice A is incorrect because a decreased concentration of C3b is not a typical indicator of inflammation. Choice C is incorrect because mannose-binding lectin (MBL) is an acute-phase reactant that increases in response to inflammation, so a decreased concentration of MBL would not be indicative of inflammation. Choice D is incorrect as it includes all options, but only B is a valid clinical indicator of inflammation.