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Ready-made multiple-choice practice quizzes, hand-checked. Take any free quiz online — every answer comes with an explanation, and every quiz page has a full answer key to revise from.
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Free · no sign-up · no time limit
Ready-made multiple-choice practice quizzes, hand-checked. Take any free quiz online — every answer comes with an explanation, and every quiz page has a full answer key to revise from.
Human body
Explore how the heart, lungs, kidneys, liver, and brain sustain life through coordinated physiological processes. Answer each question to see whether you got it right, with an explanation every time.
A free 10-question multiple-choice practice test on Human body. Each question has one correct answer and a short explanation, and the full answer key below the player doubles as a study sheet. No account, no time limit — take it as often as you like.
This is a free, 10-question multiple-choice quiz. Answer each question to see whether you got it right, with an explanation for every answer. There is no sign-up and no time limit — take it as many times as you like, and use the answer key above to revise before or after.
Correct answer: BNephron
Each kidney contains roughly one million nephrons, which regulate water balance, filter waste products, and maintain electrolyte concentrations.
Correct answer: CLiver
The liver synthesizes bile, which emulsifies fats in the small intestine, though bile is concentrated and stored in the gallbladder.
Correct answer: DAlveoli
Alveoli are microscopic air sacs surrounded by capillaries where oxygen diffuses into the blood and carbon dioxide diffuses out.
Correct answer: ALeft ventricle
The left ventricle possesses the thickest muscular wall because it must generate enough pressure to circulate oxygenated blood throughout the body.
Correct answer: CMedulla oblongata
Located in the brainstem, the medulla oblongata contains cardiac, vasomotor, and respiratory centers that sustain baseline survival.
Correct answer: BEndocrine hormone secretion and exocrine enzyme secretion
The pancreas secretes digestive enzymes into the duodenum (exocrine function) and releases insulin and glucagon directly into the bloodstream (endocrine function).
Correct answer: BDiaphragm
The diaphragm moves downward when contracting, increasing chest cavity volume and reducing internal air pressure so air rushes into the lungs.
Correct answer: ASpleen
The spleen acts as a lymphoid blood filter, recycling iron from degraded erythrocytes and storing immune cells and platelets.
Correct answer: DMitral valve
The mitral (bicuspid) valve closes during ventricular systole to ensure blood flows forward into the aorta rather than backward into the left atrium.
Correct answer: BErythropoietin
When renal tissues detect low oxygen levels in the blood, the kidneys secrete erythropoietin (EPO) to accelerate red blood cell production.