Science MCQs

Cilia and mucus in the trachea trap dust and bacteria and move them upward to be expelled.

Exercise increases the heart's workload, so pulse rate increases to supply more oxygen to muscles.

The larynx contains the vocal cords and is involved in sound production.

The pericardium is a protective membrane surrounding the heart.

Pneumonia can be caused by bacteria, viruses, or fungi and involves fluid-filled alveoli.

RBCs are biconcave discs, which increases their surface area for oxygen exchange.

Mitochondria are the organelles where aerobic respiration occurs, producing ATP.

Lime water turns milky in the presence of carbon dioxide, proving it is exhaled.

Capillaries have very thin walls (one cell thick) to facilitate the exchange of materials.

Platelets help form a clot to stop bleeding by creating a web that traps red blood cells.