Practice questions without fighting the page.

<b>Correct answer: A. Pancreas</b> <ul> <li>Insulin is an <b>endocrine hormone</b> secreted by the <b>β-cells of the islets of Langerhans in the pancreas</b>.</li> <li>It lowers blood glucose by helping cells absorb glucose and by promoting its storage as glycogen.</li> <li><b>Other organs</b> listed do not secrete insulin: liver stores glucose, gall bladder stores bile, and kidneys filter blood and regulate minerals but do not release insulin.</li> </ul> <b>Exam tip:</b> Remember “pancreas = insulin,” and think of its role in glucose uptake after meals.

<b>Answer: B. Measurement</b> <ul> <li><b>Correct reasoning:</b> Metrology is the science of measurement and measurement systems—defining units, accuracy, precision, and standards.</li> <li><b>Key concept:</b> It deals with how we quantify physical quantities and ensure comparability across times and places.</li> <li><b>Why others are incorrect:</b> <ul> <li>A (Weather) relates to atmospheric conditions, not metrology.</li> <li>C (Distance) is a quantity; metrology covers measuring all quantities, not just distance.</li> <li>D (None) is false since metrology specifically means measurement science.</li> </ul></li> <li><b>Exam tip:</b> Remember metrology = measurement science; relate to standard units (SI) and calibration.</li> </ul>

<b>Correct option: B</b> - Radio waves <ul> <li><b>Reason</b>: Radar uses radio waves to detect aircraft by sending a radio pulse and measuring its reflection (echo) from objects.</li> <li><b>Key concept</b>: Electromagnetic waves in the radio frequency range travel long distances and can reflect off metal objects like planes.</li> <li><b>Simple formula</b>: Range ~ (speed of light × time delay)/2; time delay between transmitted and received pulse gives distance.</li> <li><b>Exam tip</b>: If a question mentions detection of distant or fast-moving objects, think radio waves (radar).</li> <li><b>Why others are incorrect</b>: <ul> <li>Sound waves: attenuate in air and require detectors near the object; not used for long-range detection.</li> <li>Ultrasonic waves: high frequency, short range.</li> <li>Infrared: limited range and weather sensitivity; not suitable for radar surveillance.</li> </ul> </li> </ul>

<b>Correct option: C</b> <ul> <li><b>Correct answer text:</b> Darwin</li> <li><b>Reason:</b> The theory of Evolution was proposed by Charles Darwin, centered on natural selection driving gradual changes in species over time.</li> <li><b>Key concept:</b> Natural selection: variation exists, those better suited survive and reproduce more, passing traits to offspring.</li> <li><b>Why others are wrong:</b> Newton—gravity/physics; Mendel—principles of inheritance (gene patterns); Einstein—relativity.</li> <li><b>Exam tip:</b> Link “Darwin” with evolution and natural selection; remember Darwin’s voyage on the Beagle.</li> </ul>

<b>Answer: A</b> <ul> <li><b>Explanation:</b> Only the Stockholm Convention is not about greenhouse gases; it targets persistent organic pollutants. </li> <li><b>Key concept:</b> Kigali Amendment aims to reduce HFCs (a greenhouse gas); Kyoto Protocol sets binding GHG reduction targets. </li> <li><b>Why others are associated with GHG reduction:</b> - Kigali Amendment → phase down HFCs (high global warming potential). - Kyoto Protocol → legally binding GHG emission cuts. </li> <li><b>Exam tip:</b> Remember: Stockholm Convention = POPs, not GHGs. </li> </ul>

<b>Answer: D</b> <ul> <li><b>Malaria</b> is caused by Plasmodium parasites (protozoan), transmitted by Anopheles mosquitoes, not a virus.</li> <li><b>Smallpox</b>, <b>AIDS</b> (HIV), and <b>Flu</b> are viral diseases (virus causes infection or triggers disease).</li> <li>Key concept: viruses are distinct from parasites; malaria involves a parasite and a mosquito vector, not a viral pathogen.</li> </ul> <p>Exam tip: If a disease involves a vector like a mosquito and a parasite, it is typically not viral.</p>