If farmers exposed to 'insecticides' ('irreversible' cholinesterase inhibitors) are given medical kits that contain atropine. Which one of the following effects of the cholinesterase inhibitor will NOT be blocked by the atropine?

Correct Answer: D

Rationale: The correct answer is D. Atropine blocks the effects of cholinesterase inhibitors on muscarinic receptors but not on nicotinic receptors, which are responsible for skeletal muscle overstimulation. Atropine can block bronchoconstriction, increased bladder activity, and increased bowel motility as they are mediated by muscarinic receptors. Therefore, the effects on skeletal muscle overstimulation, leading to paralysis, will not be blocked by atropine.

Correct Answer: B

Rationale: The correct answer is B: 1 and 2 only. Sentence 1 and 2 are correct because they are grammatically accurate and logically coherent. Sentence 3 is incorrect as it contains a grammatical error. The key is to analyze each sentence independently to determine its correctness based on grammar, clarity, and logical consistency. In this case, only sentences 1 and 2 meet the criteria, making B the correct choice.

Correct Answer: A

Rationale: The correct answer is A because an endothermic reaction absorbs thermal energy from the surroundings to proceed. In an endothermic reaction, the products have higher potential energy than the reactants, requiring energy input. Choice B is incorrect as endothermic reactions do not transfer thermal energy to the surroundings. Choices C and D are incorrect as they describe exothermic reactions, where thermal energy is released to the surroundings.

Correct Answer: B

Rationale: The correct answer is B (green, violet) because green has a lower frequency than violet in the visible light spectrum. Green light has a wavelength longer than violet light, meaning it has lower frequency. This is based on the electromagnetic spectrum where colors are arranged in order of increasing frequency from red (lowest) to violet (highest). Other choices are incorrect because they do not follow the order of increasing frequency as per the visible light spectrum.

Correct Answer: B

Rationale: The correct answer is B: iodine. Iodine is an essential element required for the synthesis of thyroid hormone. Thyroid hormones such as thyroxine (T4) and triiodothyronine (T3) contain iodine atoms. Without sufficient iodine, the thyroid gland cannot produce these hormones, leading to thyroid disorders like hypothyroidism or goiter. Copper (A), sulfur (C), and zinc (D) are not directly involved in the synthesis of thyroid hormone. Copper is important for enzyme function, sulfur is present in amino acids, and zinc is involved in various cellular processes but not specifically in thyroid hormone synthesis.