Body System

What do we breathe in?

• A) Carbon dioxide

• B) Nitrogen

• C) Oxygen

• D) Hydrogen

What is the main function of red blood cells?

• A) Fight infections

• B) Carry oxygen to cells

• C) Help blood clot

• D) Transport waste

Which blood vessel carries blood back to the heart?

• A) Arteries

• B) Veins

• C) Capillaries

• D) Plasma

Which of the following statements describes the function of the heart?

• The heart produces white and red blood cells.

• The heart controls the nervous system.

• The heart makes oxygen and carbon dioxide.

• The heart pumps blood throughout the body.

Why do red blood cells lack a nucleus?

• A) To reduce their weight

• B) To allow more room for haemoglobin

• C) To move more easily through capillaries

• D) To help them fight infections

Which component of blood is most responsible for regulating body temperature?

• A) Platelets

• B) Plasma

• C) Red blood cells

• D) White blood cells

Where does gas exchange take place in the lungs?

• A) Trachea

• B) Bronchioles

• C) Alveoli

• D) Diaphragm

What is the primary role of cilia in the trachea?

• A) To move oxygen directly into the bloodstream

• B) To sweep trapped particles and mucus upward for removal

• C) To humidify incoming air

• D) To prevent the trachea from collapsing

Why are alveoli surrounded by a dense network of capillaries?

• A) To increase the speed of air flow into the lungs

• B) To maintain a constant blood pressure in the lungs

• C) To maximize the exchange of oxygen and carbon dioxide

• D) To keep the alveoli moist for gas exchange

What connects bones to muscles?

• A) Ligaments

• B) Tendons

• C) Cartilage

• D) Bone marrow