Body fluids and circulation practice · Easy

Option C (Open circulatory system) is correct because haemolymph is the fluid found in organisms with open circulatory systems.

Option B (A-muscular chambered heart, B-2, C-3, D-4) is correct because all vertebrates have a muscular chambered heart, fishes have a 2-chambered heart, amphibians and reptiles have a 3-chambered heart, and birds and mammals have a 4-chambered heart.

Option A (A-Semilunar; B-Dub) is correct because the semilunar valves close during ventricular diastole, producing the second heart sound, "Dub".

Option B (lymphocytes) is correct because lymphocytes are the primary cells responsible for providing immunity through antibody production and cell-mediated responses.

Option D (Return interstitial fluid to the blood) is correct because the primary function of lymph is to return excess interstitial fluid and leaked proteins to the bloodstream.

Option B (Initiation of heart beat) is correct because the SA-node is the heart's natural pacemaker, responsible for initiating the heartbeat.

Option B (Blood from the pulmonary vein and vena cava flows into left and right ventricles, respectively) is correct because the bicuspid and tricuspid valves open to allow blood to flow from the atria into the ventricles.

Option D is the wrong statement because blood group O has no antigens on the surface of RBCs, but it does have both anti-A and anti-B antibodies in the plasma.

Option B is correct because the liver detoxifies ammonia and converts it into urea, which is then transported in the blood to the kidneys for excretion.

Option C (4-10 min) is correct because the normal blood clotting time in humans typically ranges from 4 to 10 minutes.

Option C (ventricular systole) is correct because blood pressure is at its maximum during the contraction of the ventricles.

Option B (In the wall of right atrium) is correct because the sinoatrial (SA) node, which acts as the heart's natural pacemaker, is located in the wall of the right atrium.

Option D (Oxygenated blood is pumped into the aorta and deoxygenated blood is pumped into the pulmonary artery) is correct because during ventricular systole, the left ventricle pumps oxygenated blood into the aorta, and the right ventricle pumps deoxygenated blood into the pulmonary artery.

Option A (After the auricular/atrial systole) is correct because ventricular systole occurs after the atria have contracted to fill the ventricles.

Option D (Red bone marrow) is correct because in adult mammals, erythrocytes (red blood cells) are formed in the red bone marrow.

Option B (If both A and R are true, but R is not the correct explanation of A) is correct because both Thrombin being essential for blood clotting and Calcium ions playing an important role in blood clotting are true statements, but calcium's role is not the primary reason why thrombin is essential.

Option B (Atherosclerosis) is correct because it is the narrowing of arteries due to the deposition of calcium, fat, cholesterol, and fibrous tissue.

Option B (Difference in electric potential) is correct because an ECG measures the electrical potential differences generated by the heart.

Option B (SA-node → AV-node → Bundle of His → Purkinje fibres) is correct because it represents the correct sequence of impulse transmission in the heart.

Option C (Immune responses) is correct because lymphocytes, specifically B and T cells, are the key cells responsible for adaptive immunity.

Option A (120 mm Hg) is correct because the normal systolic blood pressure in an adult human is approximately 120 mm Hg.

Option A (Intestine to Liver) is correct because the hepatic portal vein specifically transports blood from the intestine to the liver for processing.

Option B (whale) is correct because whales, being mammals, have a double circulatory system with separate pulmonary and systemic pathways.

Option A (P-wave) is correct because the P-wave on an ECG represents atrial depolarization.

Option C (Depolarisation of Atria) is correct because the P wave on an ECG represents the electrical activity associated with atrial depolarization.

Option D (lacking clotting factors) is correct because serum is blood plasma from which the clotting factors have been removed, typically by allowing the blood to clot.

Option A (Formation of prothrombin) is correct because Vitamin K is essential for the synthesis of prothrombin, a key clotting factor, in the liver.

Option A (If both Assertion and Reason are correct and Reason is the correct explanation of Assertion) is correct because monocytes, though a smaller percentage of WBCs, are crucial phagocytic cells.

Option A (A-left atria, B-right atria) is correct because oxygenated blood enters the left atria and deoxygenated blood enters the right atria in birds and mammals.

Option C (Left ventricle and left auricle) is correct because the bicuspid (mitral) valve is located between the left atrium (auricle) and the left ventricle.