Which atmospheric layer has lowest temperature? A. Troposphere B. Stratosphere C. Mesosphere D. Thermosphere Explanation: Mesosphere is coldest.
Which ocean has deepest trench? A. Atlantic B. Indian C. Pacific D. Arctic Explanation: Mariana Trench is in Pacific.
Which boundary recycles crust? A. Divergent B. Transform C. Convergent D. Rift Explanation: Subduction recycles crust.
Which rock shows banding? A. Granite B. Basalt C. Gneiss D. Limestone Explanation: Gneiss has distinct layers.
Which gas is responsible for photochemical smog? A. O₂ B. NO₂ C. CO₂ D. N₂ Explanation: Nitrogen dioxide forms smog.
Which ecological pyramid is always upright? A. Energy B. Biomass C. Number D. Population Explanation: Energy decreases at each trophic level.
Which hormone controls metabolism rate? A. Insulin B. Thyroxine C. Adrenaline D. Estrogen Explanation: Thyroxine regulates metabolic rate.
Which blood protein transports iron? A. Hemoglobin B. Albumin C. Transferrin D. Fibrin Explanation: Transferrin carries iron.
Which stage aligns chromosomes at equator? A. Prophase B. Metaphase C. Anaphase D. Telophase Explanation: Chromosomes line up in metaphase.
Which RNA is structural component of ribosome? A. mRNA B. tRNA C. rRNA D. snRNA Explanation: rRNA forms ribosomal structure.