Please refer to Body Fluids and Circulation Class 11 Biology Important Questions with answers below. These solved questions for Chapter 18 Body Fluids and Circulation in NCERT Book for Class 11 Biology have been prepared based on the latest syllabus and examination guidelines issued by CBSE, NCERT, and KVS. Students should learn these solved problems properly as these will help them to get better marks in your class tests and examinations. You will also be able to understand how to write answers properly. Revise these questions and answers regularly. We have provided Notes for Class 11 Biology for all chapters in your textbooks.

Important Questions Class 11 Biology Chapter 18 Body Fluids and Circulation

Objective Question

Question. Lymph is modified blood that contains
(a) RBC and WBC
(b) RBC, WBC and protein
(c) WBC and all protein
(d) all contents of blood except RBC and certain protein

Question. Which one engulfs pathogens rapidly?
(a) Acidophils
(b) Monocytes
(c) Basophils
(d) Neutrophils

Question. Which of the following is considered as the soldiers of body?
(a) Lungs
(b) Capillaries
(c) Red blood cells
(d) White blood cells

Question. What is correct for blood group ‘O’?
(a) No antigens but both a and b antibodies are present
(b) A antigen and b antibody
(c) Antigen and antibody both absent
(d) A and B antigens and a, b antibodies

Question. When the blood of a foetus is agglutinated by its mother’s Rh antibodies, then which of the following condition arises as a severe anaemia?
(a) Immunization
(b) Ectopic pregnancy
(c) Erythroblastosis foetalis
(d) Both (b) and (c)

Question. Which of the following cations is required for the conversion of prothrombin into active thrombin by thromboplastin?
(a) Cu²⁺ 
(b) Fe³⁺
(c) Fe²⁺ 
(d) Ca²⁺

Question. Fish has ___(i)____ and ___(ii)___ circulatory system.
(a) (i)- open, (ii)- single
(b) (i)- open, (ii)- double
(c) (i)- closed, (ii)- single
(d) (i)- closed, (ii)- double

Question. Which of the following set of animals has an incomplete double circulation system ?
(a) Frog and crocodile
(b) Shark and whale
(c) Lizard and pigeon
(d) Toad and lizard

Question. Nodal tissue/musculature in human heart has
(a) the ability to generate action potential due to any external stimuli.
(b) two patches, one in atrium and other in ventricle.
(c) purkinje fibres throughout the ventricular musculature.
(d) atrioventricular node, also called pacemaker.

Question. The pacemaker of the human heart is
(a) SA node
(b) tricuspid valve
(c) AV node
(d) SV node

Statement Type Questions

Question. Given below are four statements (a-d) regarding human blood circulatory system
(i) Arteries are thick-walled and have narrow lumen as compared to veins.
(ii) Angina is acute chest pain when the blood circulation to the brain is reduced.
(iii) Persons with blood group AB can donate blood to any person with any blood group under ABO system.
(iv) Calcium ions play a very important role in blood clotting.
Which two of the above statements are correct?
(a) (i) & (iv)
(b) (i) & (ii)
(c) (ii) & (iii)
(d) (iii) & (iv)

Question. Find out the incorrect statement from the following.
(a) Veins are typically larger in diameter than arteries.
(b) Because of their small size, capillaries contain blood that is moving more quickly than in other parts of the circulatory system.
(c) The walls of arteries are elastic, enabling them to stretch and shrink during changes in blood pressure.
(d) Veins contain more blood than any other part of the circulatory system.

Question. Cardiac output is/are
(i) Product of heart rate and stroke volume.
(ii) Product of auricular and ventricular volume.
(iii) A process in which blood pumped in one minute.
Which of the above statements is true ?
(a) Only (i)
(b) Only (ii)
(c) Both (i) and (ii)
(d) Both (i) and (iii)

Matching Type Questions

Question. Which one of the following is a matching pair?
(a) Lubb-Sharp closure of AV valves at the beginning of ventricular systole.
(b) Dup-Sudden opening of semilunar valves at the beginning of ventricular diastole.
(c) Pulsation of the radial artery-Valves in the blood vessels.
(d) Purkinje fibres-Initiation of the heart beat.

Question. Match the following descriptions (given in column-II) of each type of blood cell to their names (given in column-I).

Column-I (Blood cell)	Column-II (Description)
A. Erythrocyte	I. Most abundant white blood cell, and the main phagocytic cell of the blood.
B. Eosinophil	II. Least abundant white blood cell; releases histamine granules.
C. Lymphocyte	III. Resist infections and are associated with allergic reactions.
D. Neutrophil	IV. Blood cell that contains haemoglobin and transports oxygen.
E. Basophil	V. Specialized antibodyproducing white blood cells.

(a) A – IV; B – III; C – V; D – I; E – II
(b) A – I; B – II, C – III; D – IV; E – V
(c) A – II; B – III; C – I; D – V; E – IV
(d) A – IV; B – I; C – II; D – III; E – V

Question. Match each area of the heart (column-I) with the structure (column-II) from which it receives blood.

Column-I (Area of heart)	Column-II (Receives blood from)
A. Right atrium	I. Left atrium
B. Right ventricle	II. Vena cavae
C. Left atrium	III. Right atrium
D. Left ventricle	IV. Pulmonary veins

(a) A – II; B – III; C – IV; D – I
(b) A – I; B – II; C – III; D – IV
(c) A – IV; B – I; C – II; D – III
(d) A – III; B – IV; C – I; D – II

Critical Thinking Type Questions

Question. If a person is loosing blood continuously due to injury then what will be the effect on his pulse and BP initially?
(a) Pulse and BP both will fall.
(b) Pulse will fall and BP will rise.
(c) Both pulse and BP will rise.
(d) Pulse will rise and BP will fall.

Question. In normal human blood pressure, what does the “120” represent?
(a) The maximum pressure that can be sustained by the arteries before bursting.
(b) The lowest pressure in the arteries that will keep someone from fainting when they stand up.
(c) The highest ideal arterial pressure for someone at rest.
(d) The pressure in the veins.

Question. Sinus venosus is/are present in which of the following animals?
(i) Fishes
(ii) Amphibians
(iii) Reptiles
(iv) Birds
(v) Mammals
(a) (i) only
(b) (i) and (iv) only
(c) (i), (ii) and (iii)
(d) (i), (iii) and (iv)

Question. Which of the following is not correct for blood pressure?
(i) It is not affected by atherosclerosis.
(ii) It is typically lower in veins than in arteries.
(iii) Diastolic pressure is higher than systolic pressure.
(iv) It is usually refers to as venous pressure of the systemic circulation.
(a) (i) & (iii)
(b) (i), (ii) & (iii)
(c) (ii) & (iii)
(d) (i), (iii) & (iv)

Question. “X” is a fibrous tissue of the membranous septum of the heart just above the septal cusp of the tricuspid valve. It separates the atrium and the ventricle of the same side. Identify “X”.
(a) Sino atrial node
(b) Atrioventricular septum
(c) Atrioventricular node
(d) Interventricular septum

Question. When a leopard runs after you, the increase in heart rate is probably due to the __________.
(a) hypothalamus
(b) sympathetic nerves
(c) increase in blood pressure
(d) medullary accelerator centre