Question

1. which organ pumps blood throughout the body?

a) lungs
b) brain
c) liver
d) heart

1. which blood vessels carry blood away from the heart?

a) capillaries
b) arteries
c) venules
d) veins

1. which blood vessels have valves?

a) arterioles
b) capillaries
c) veins
d) arteries

1. what is the liquid part of blood called?

a) plasma
b) lymph
c) platelets
d) hemoglobin

1. which cells carry oxygen?

a) plasma
b) red blood cells
c) white blood cells
d) platelets

1. which cells fight infection?

a) red blood cells
b) white blood cells
c) plasma
d) platelets

1. what helps blood clot to stop bleeding?

a) platelets
b) red blood cells
c) white blood cells
d) plasma

1. how many chambers does the human heart have?

a) 3
b) 4
c) 2
d) 1

1. the upper chambers of the heart are called:

a) aortas
b) ventricles
c) atria
d) valves

1. the lower chambers of the heart are called:

a) veins
b) atria
c) septum
d) ventricles

Explanation:

1. The heart is the organ that pumps blood throughout the body. Lungs are for respiration, brain for nervous functions, liver for metabolism. So answer D.
2. Arteries carry blood away from the heart. Capillaries are for exchange, venules and veins carry blood to the heart. So answer B.
3. Veins have valves to prevent backflow. Arterioles and capillaries don't have valves, arteries have different valve mechanisms. So answer C.
4. Plasma is the liquid part of blood. Lymph is for lymphatic system, platelets are cell fragments, hemoglobin is in red blood cells. So answer A.
5. Red Blood Cells carry oxygen via hemoglobin. Plasma is liquid, white blood cells fight infection, platelets clot. So answer B.
6. White Blood Cells fight infection. Red blood cells carry oxygen, plasma is liquid, platelets clot. So answer B.
7. Platelets help blood clot. Red blood cells carry oxygen, white blood cells fight infection, plasma is liquid. So answer A.
8. The human heart has 4 chambers (2 atria, 2 ventricles). So answer B.
9. The upper chambers of the heart are atria. Aortas are arteries, ventricles are lower chambers, valves regulate flow. So answer C.
10. The lower chambers of the heart are ventricles. Veins carry blood, atria are upper chambers, septum divides heart. So answer D.

Answer:

1. D. Heart
2. B. Arteries
3. C. Veins
4. A. Plasma
5. B. Red Blood Cells
6. B. White Blood Cells
7. A. Platelets
8. B. 4
9. C. Atria
10. D. Ventricles