Who discovered the nucleus of an atom? MCQ with Answer and Explanation

Explanation:
Amylase (present in saliva and pancreatic juice) hydrolyses starch into maltose and dextrins. Pepsin digests proteins in the stomach. Lipase breaks down fats. Trypsin also digests proteins. Enzymes are specific biocatalysts.

Explanation:
Graphite slows down fast neutrons in nuclear reactors, enabling sustained chain reaction. Diamond is hard and insulating; fullerenes are nanomaterials; charcoal is adsorbent.

Explanation:
Combustion of methane (CH₄ + 2O₂ → CO₂ + 2H₂O + heat) is an exothermic reaction, releasing heat to surroundings. Melting, evaporation, and sublimation are endothermic phase changes requiring heat absorption to overcome intermolecular forces. Exothermic reactions: burning, respiration, neutralization (usually), condensation, freezing. Endothermic: photosynthesis, cooking, melting, boiling.