Explanation

• Heart rate increases during exercise due to increased sympathetic nervous system activity releasing norepinephrine.
• This prepares the body for higher oxygen and energy demand.
• It increases heart pumping strength and speed.
• More blood reaches muscles for ATP production.
• This is a normal physiological response during physical activity.

Last verified on 14-06-2026

Explanation

• The smooth endoplasmic reticulum (SER) is responsible for drug detoxification in liver cells.
• It contains enzymes that break down harmful drugs and toxins.
• This process makes substances less toxic and easier to excrete.
• Liver cells have abundant SER for this function.

Last verified on 14-06-2026

Explanation

• Alcohol acts as a depressant because it enhances GABA activity in the brain, which slows nerve signals.
• GABA is an inhibitory neurotransmitter that reduces brain activity.
• This leads to relaxation, slower reactions, and reduced coordination.
• Alcohol also suppresses excitatory signals.
• That is why it causes drowsiness and impaired judgment.

Last verified on 14-06-2026

Explanation

• The stomach secretes hydrochloric acid (HCl) to activate pepsinogen into pepsin for protein digestion.
• HCl creates an acidic environment in the stomach.
• This acidity helps enzymes work properly.
• It also kills harmful microbes in food.
• Thus, it supports digestion and protection.

Last verified on 14-06-2026

Explanation

• Drinking too much water quickly causes harm because it dilutes sodium levels in the blood (hyponatremia).
• Low sodium disrupts normal nerve and muscle function.
• Cells may swell due to water imbalance.
• This can affect brain function and become dangerous.

Last verified on 14-06-2026

Explanation

• Lactic acid builds up in muscles because oxygen supply becomes insufficient during intense exercise.
• Muscles switch to anaerobic respiration for quick energy.
• This produces lactic acid as a by-product.
• Accumulation causes muscle fatigue and burning sensation.
• It is a temporary process until oxygen levels recover.

Last verified on 14-06-2026

Explanation

• Butter melts faster than ghee.
• Because it contains more water and milk solids, making its structure less stable.
• Water in butter lowers its melting stability at room temperature.
• This makes butter softer and quicker to melt.

Additional information:

• Ghee is almost pure fat with no water content.
• Ghee remains more stable because it is more refined.

Last verified on 14-06-2026

Explanation

• Zinc is commonly used in toothpaste.
• Because it helps reduce bacterial growth and controls bad breath.
• Zinc compounds (like zinc citrate or zinc chloride) kill or inhibit oral bacteria.
• It also helps reduce plaque formation.
• This improves overall oral hygiene.

Last verified on 14-06-2026

Explanation

• Bread rises faster in a warm kitchen because heat increases yeast activity (respiration).
• Yeast produces more carbon dioxide gas in warm conditions.
• This gas forms bubbles that make dough expand.
• In cold temperatures, yeast works slowly.

Last verified on 14-06-2026

Explanation

• Soap lathers better in soft water because hard water contains calcium (Ca²⁺) and magnesium (Mg²⁺) ions that react with soap to form insoluble salts.
• These salts reduce soap’s ability to produce foam.
• Soft water does not contain these ions, so soap works fully.
• More soap remains active in soft water for lather formation.

Last verified on 14-06-2026