Which type of immunity is immediate? A. Active B. Passive C. Adaptive D. Natural Explanation: Passive immunity provides instant antibodies.
Which hormone increases heart rate? A. Insulin B. Adrenaline C. Thyroxine D. Estrogen Explanation: Adrenaline stimulates cardiac activity.
Which structure carries oxygen in blood? A. Plasma B. Hemoglobin C. Platelets D. Antibodies Explanation: Hemoglobin binds oxygen.
Which stage of mitosis separates sister chromatids? A. Prophase B. Metaphase C. Anaphase D. Telophase Explanation: Chromatids move to opposite poles.
Which organelle contains hydrolytic enzymes? A. Mitochondria B. Lysosome C. Golgi D. Ribosome Explanation: Lysosomes digest cellular waste.
Which process generates NADH? A. Glycolysis B. Photosynthesis light reaction C. Fermentation only D. Translation Explanation: Glycolysis produces NADH.
Which functional group is most reactive in nucleophilic substitution? A. Alkane B. Alkyl halide C. Alkene D. Aromatic ring Explanation: Leaving group facilitates substitution.
Which hybridization is present in benzene carbon? A. sp B. sp² C. sp³ D. dsp² Explanation: Benzene carbons are trigonal planar.
Which reaction proceeds via carbocation rearrangement? A. SN2 B. SN1 C. E2 D. Addition Explanation: SN1 involves carbocation intermediates.
Which is most stable carbocation? A. Primary B. Secondary C. Tertiary D. Methyl Explanation: Tertiary stabilized by hyperconjugation.