Body Fluids and Circulation — Class 11 MCQs with Answers
Class 11 CBSE Biology · Chapter 15
90 practice questions · 30 Easy · 30 Medium · 30 Hard · Updated
Practise the most important Class 11 CBSE Biology questions from Chapter 15, "Body Fluids and Circulation". You get 9 timed quizzes made from 90 NCERT-based MCQs, with answers and explanations. The questions are split into 30 Easy, 30 Medium and 30 Hard. Warm up on the basics, then move on to the exam-level questions that set top scorers in CBSE & Maharashtra HSC Board exams, MHT-CET and NEET UG apart.
To score well in "Body Fluids and Circulation", focus on diagrams, key terms and knowing NCERT line by line. Each MCQ here is timed and uses exam-style marking (+4 correct, −1 wrong, 0 skipped). This trains you to stay accurate under time pressure, as real papers need. Every question has a short explanation, so a wrong answer becomes a quick lesson. It is the fastest way to fix gaps before a test.
Use this chapter for focused revision. Start with the Easy set to check your basics on Body Fluids and Circulation, then move to Medium and Hard to practise applying them. Your accuracy, streaks and XP save automatically. This chapter also adds to your overall Class 11 Biology mastery score. 14 sample questions are solved in full below, with the answer and a worked explanation. Sign in free to start practising.
Key concepts: Body Fluids and Circulation (Class 11 Biology)
Blood and lymph are the fluid connective tissues that move nutrients, gases and wastes. This chapter details plasma and formed elements, ABO and Rh grouping, clotting, the four-chambered heart, the events and sounds of the cardiac cycle, the ECG, and the double-circulation plan of mammals.
- Blood as connective tissue
- Blood is a fluid connective tissue of straw-coloured plasma (~55%) and formed elements (~45%) — erythrocytes, leucocytes and platelets.
- Plasma
- Plasma is 90–92% water carrying proteins (albumin, globulins, fibrinogen), ions, glucose and wastes; serum is plasma minus the clotting factors.
- Erythrocytes (RBCs)
- Red cells are biconcave and enucleate, packed with haemoglobin; about 5 million per mm³, formed in bone marrow and living roughly 120 days.
- Leucocytes (WBCs)
- White cells are nucleated and immune: granulocytes (neutrophils, eosinophils, basophils) and agranulocytes (lymphocytes, monocytes).
Body Fluids and Circulation — important questions & MCQs with answers (Class 11 Biology)
14 solved questions from this chapter's difficulty levels, each with its answer and explanation. The other 76 are timed and scored when you sign in.
- Q1Easy
RBCs in adults are produced in:
A.Bone marrow✓ CorrectB.LiverC.SpleenD.HeartAnswer: A. Bone marrow
Explanation: In adults RBCs are produced in red bone marrow of long bones, sternum and ribs (erythropoiesis); the liver and spleen only make RBCs in the foetus, the usual mix-up in this question.
- Q2Easy
Human heart has:
A.2B.3C.4 chambers✓ CorrectD.5Answer: C. 4 chambers
Explanation: The human heart has two atria and two ventricles — four chambers total. Fish have two chambers, amphibians and most reptiles three, so chamber count also tracks how complete circulation is.
- Q3Easy
Which of the following is a fluid connective tissue in humans?
A.CartilageB.Blood✓ CorrectC.BoneD.AdiposeAnswer: B. Blood
Explanation: Blood and lymph are the two fluid connective tissues in humans — their cells sit in a liquid plasma matrix rather than the solid matrix of cartilage or bone. Adipose tissue's matrix is not fluid at all.
- Q4Easy
The most abundant plasma protein is:
A.FibrinogenB.GlobulinC.Albumin✓ CorrectD.ProthrombinAnswer: C. Albumin
Explanation: Albumin is the most abundant plasma protein (about 60% of the total) and its job is maintaining colloid osmotic pressure so water stays in the vessels. Globulins carry antibodies and fibrinogen is reserved for clotting, both far less abundant.
- Q5Easy
Heart is enclosed within a double-walled membrane called:
A.MeningesB.PleuraC.PeritoneumD.Pericardium✓ CorrectAnswer: D. Pericardium
Explanation: The pericardium is the double-walled sac enclosing the heart, with pericardial fluid between its layers reducing friction during beating. Meninges cover the brain, pleura the lungs, and peritoneum the abdominal organs.
- Q6Easy
Open circulatory system is found in which group?
A.VertebratesB.AnnelidsC.Arthropods and molluscs✓ CorrectD.CephalochordatesAnswer: C. Arthropods and molluscs
Explanation: Arthropods and most molluscs have open circulation: blood (haemolymph) leaves vessels and bathes tissues directly in the haemocoel. Vertebrates and annelids instead have closed systems where blood stays inside vessels.
- Q7Medium
Plasma constitutes about ___ of blood volume.
A.95%B.5%C.55%✓ CorrectD.30%Answer: C. 55%
Explanation: Blood is roughly 55% plasma (liquid matrix) and 45% formed elements — mostly RBCs, the packed-cell volume seen in a haematocrit tube. 5% and 30% undercount plasma; 95% ignores the cells.
- Q8Medium
Pacemaker of human heart:
A.Purkinje fibresB.AV nodeC.Bundle of HisD.SA node✓ CorrectAnswer: D. SA node
Explanation: The SA node in the right atrial wall self-generates the fastest rhythm (~70–75/min) and sets heart rate, hence 'pacemaker'. The AV node only relays and delays the impulse; Purkinje fibres and the Bundle of His just conduct it onward.
- Q9Medium
Which is NOT a function of the lymphatic system?
A.Immune surveillanceB.Absorption of fats from intestineC.Return of interstitial fluid to bloodD.Transport of CO₂ to lungs✓ CorrectAnswer: D. Transport of CO₂ to lungs
Explanation: The lymphatic system drains excess tissue fluid back to blood, carries absorbed fats from the intestine, and hosts immune surveillance — but it does not transport respiratory gases like CO₂, which stays a job for blood alone.
- Q10Medium
Which ion is essential for blood clotting?
A.Ca²⁺✓ CorrectB.Na⁺C.K⁺D.Cl⁻Answer: A. Ca²⁺
Explanation: Ca²⁺ ions are essential cofactors that activate prothrombin and several other clotting factors during coagulation. Na⁺, K⁺ and Cl⁻ maintain osmotic and electrical balance but play no direct role in clot formation.
- Q11Medium
Human heart is described as myogenic because:
A.Beat depends on hormones onlyB.Beat is initiated by vagus nerveC.Beat is initiated by spinal cordD.Heartbeat is initiated by specialized cardiac muscle (SA node)✓ CorrectAnswer: D. Heartbeat is initiated by specialized cardiac muscle (SA node)
Explanation: 'Myogenic' means the heartbeat originates within specialised cardiac muscle itself — the SA node — rather than needing a nerve or hormonal trigger to start each beat. Nerves like the vagus only speed up or slow that intrinsic rhythm.
- Q12Hard
Universal donor blood group:
A.AB-positiveB.O-negative✓ CorrectC.A-positiveD.B-negativeAnswer: B. O-negative
Explanation: O-negative RBCs carry no A, B or Rh(D) antigens, so any recipient's immune system leaves them alone — making it the universal donor group. AB is the universal recipient instead, since its plasma carries no anti-A or anti-B antibodies.
- Q13Hard
Mammals have ___ circulation.
A.NoneB.SingleC.OpenD.Double (pulmonary + systemic)✓ CorrectAnswer: D. Double (pulmonary + systemic)
Explanation: In double circulation blood passes through the heart twice per full circuit — once via the pulmonary loop to the lungs, once via the systemic loop to the body — keeping oxygenated and deoxygenated blood separate, unlike fish's single circuit.
- Q14Hard
Assertion: Lymph returns interstitial fluid to blood. Reason: Lymph contains more RBCs than blood.
A.Both falseB.Both true; R explains AC.Both true; R does not explain AD.A true, R false✓ CorrectAnswer: D. A true, R false
Explanation: Lymph does return interstitial fluid to blood, so the assertion holds — but the reason is false: lymph is characteristically devoid of RBCs (that's what makes it colourless), not richer in them, so it cannot explain the assertion.
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Start this chapter free →Body Fluids and Circulation — FAQs
What are the key concepts in Class 11 Biology Body Fluids and Circulation?+
Blood and lymph are the fluid connective tissues that move nutrients, gases and wastes. This chapter details plasma and formed elements, ABO and Rh grouping, clotting, the four-chambered heart, the events and sounds of the cardiac cycle, the ECG, and the double-circulation plan of mammals. Key ideas include Blood as connective tissue, Plasma, Erythrocytes (RBCs), Leucocytes (WBCs).
What does Class 11 Biology Chapter 15 (Body Fluids and Circulation) cover on XamBaaz?+
It has 90 NCERT-based MCQs on "Body Fluids and Circulation": 30 Easy, 30 Medium and 30 Hard. Together they make 9 timed quizzes, and you never get the same set twice. Every question has an instant explanation. They help you prepare for CBSE & Maharashtra HSC Board exams, MHT-CET and NEET UG.
Are these "Body Fluids and Circulation" questions free to practise?+
Yes. Sign in with Google to practise "Body Fluids and Circulation" free. Full unlimited access is ₹999/year on a launch offer until 1 December 2026. No chapter is charged separately.
How should I revise "Body Fluids and Circulation" for the exam?+
Start with the Easy quiz to check your basics, then try Medium and Hard to practise applying them. There are 9 timed quizzes on this chapter, so you can come back for a fresh set instead of one you have seen. Read each explanation, retry the questions you miss, and track your accuracy until it stays high.
Are these "Body Fluids and Circulation" MCQs available with answers?+
Yes. 14 sample questions are shown here in full, each with the correct option and a step-by-step "Why" explanation. Sign in free with Google to start practising, with instant scoring.
Is there negative marking in the "Body Fluids and Circulation" quizzes?+
Yes. The timed quizzes use exam-style marking: +4 for a right answer, −1 for a wrong one and 0 for a skip, the same negative marking as NEET UG. MHT-CET and CBSE board papers have no negative marking. Our mocks for those are scored their way.
What are the important questions from Body Fluids and Circulation (Class 11 Biology)?+
The questions that matter most test Blood as connective tissue, Plasma, Erythrocytes (RBCs), Leucocytes (WBCs). This page shows 14 solved important MCQs with answers and explanations; all 90 questions on the chapter are available as timed quizzes once you sign in.
Is there an online quiz for Body Fluids and Circulation?+
Yes — Class 11 Biology Body Fluids and Circulation has timed online quizzes at Easy, Medium and Hard levels, with instant scoring and a worked explanation on every question. The first quiz on the chapter is free.