Science MCQs

The nasal passage contains hair and mucus that trap dust and bacteria, and it also warms and moistens the air.

The epiglottis is a lid that covers the glottis (opening to the trachea) to prevent food from entering.

Alveoli are tiny air sacs surrounded by capillaries where gaseous exchange takes place via diffusion.

Inhalation (or inspiration) is the process of drawing air into the lungs.

When the diaphragm contracts, it flattens, increasing the volume of the chest cavity and drawing air in.

Aerobic respiration produces carbon dioxide, water, and energy (ATP). Glucose + Oxygen → CO2 + H2O + Energy.

ATP (Adenosine Triphosphate) is the energy currency of the cell, released when glucose is broken down.

Anaerobic respiration is the breakdown of food to release energy without using oxygen.

When muscles respire anaerobically (e.g. during intense exercise), they produce lactic acid and energy.

Arteries carry oxygenated blood away from the heart to the body (except pulmonary artery).