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What is the main characteristic of blood that makes it red?

• It is mostly water.

• It contains a lot of red blood cells.

• It has white blood cells.

• It moves around the body.

Which part of the blood is a very pale yellow liquid?

• Red blood cells

• White blood cells

• Blood plasma

• Hemoglobin

What are the small, numerous cells in the blood that don't have nuclei?

• White blood cells

• Blood plasma

• Red blood cells

• Pathogens

What is the purpose of the dark purple areas shown in the white blood cells in the photograph?

• They are red blood cells.

• They are parts of hemoglobin.

• They are nuclei.

• They are pathogens.

What is the function of red blood cells as described in the text?

• To fight infection

• To transport oxygen

• To produce antibodies

• To clot blood

What is the red pigment found in red blood cells that helps carry oxygen?

• Plasma

• Cytoplasm

• Hemoglobin

• Nucleus

Where does oxygen from the air first diffuse into the blood?

• In the body cells

• In the heart

• In the alveoli (air sacs) in the lungs

• In the stomach

What is formed when oxygen combines with hemoglobin inside a red blood cell?

• Carbon dioxide

• Glucose

• Oxyhaemoglobin

• Antibodies

After delivering oxygen to body cells, where does the blood travel next?

• To the stomach

• Back to the lungs to collect more oxygen

• To the brain

• To the bones

Why do red blood cells not have a nucleus?

• To make them stronger

• To allow more space for hemoglobin to carry oxygen

• To help them fight pathogens

• To make them able to move faster