In the redox reaction Zn + CuSO₄ → ZnSO₄ + Cu, the reducing agent is: MCQ with Answer and Explanation

Explanation:
Enzymes are biological catalysts that function optimally at moderate temperatures (around 35-40°C for human enzymes). Most enzymes denature and lose activity at temperatures above 50-60°C, as the protein structure unfolds. They are highly specific (lock-and-key model), protein in nature, and lower activation energy without being consumed. Some thermophilic bacteria have enzymes active at high temperatures, but typical enzymes are not stable at >100°C.

Explanation:
Methane (CH₄) is a potent greenhouse gas, absorbing infrared radiation. Oxygen and nitrogen are diatomic and do not absorb IR. Argon is a noble gas, inert. Greenhouse gases include CO₂, CH₄, N₂O, CFCs, H₂O vapor.

Explanation:
Gastric juice in the stomach contains hydrochloric acid (HCl) which aids digestion and kills bacteria. Orange juice contains citric acid, vinegar acetic acid, milk lactic acid (from fermentation). The pH of stomach acid is around 1-2.