1- (d) Lymph is a clear yellowish, slightly alkaline, coagulable fluid containing white blood cells in a liquid resembling blood plasma. It is composed of fluid matrix, plasma, white blood corpuscles or leucocytes.

2- (d) Neutrophils are a type of leucocyte (WBCs) that can take all types of stain (acid-basic-Neutral). It is most abundant (60 –70% of total WBCs) and most active type of WBCs i.e., they are the most actively phagocytic in nature.18 min video on complete WBC below

3- (d) Leucocytes are colourless, nucleated amoeboid cells found in blood which are devoid of haemoglobin and are capable of coming out of blood capillaries through the process of diapedesis. Fall of WBC count is called leucopenia, and occurs due to folic acid deficiency and AIDS, etc.

The thymus makes white blood cells called T lymphocytes (also called T cells). These are an important part of the body's immune system, which helps us to fight infection. The thymus produces all our T cells before we become teenagers. 

4- (c) Blood clotting (coagulation) is the process by which blood vessels repair ruptures after injury. Injury repair actually begins even before clotting does, through vascular spasm, or muscular contraction of the vessel walls, which reduces blood loss. Clotting itself is a complex cascade of reactions involving platelets, enzyme, and structural proteins. Calcium plays an important role by working together with vitamin K and a protein called fibrinogen in the clotting cascade.

Video 5min

5-(d) Thrombokinase hydrolyses prothrombin to thrombin in presence of Ca2+.Thrombin converts soluble fibrinogen to insoluble fibrin.

6-(c) Fish has closed and single circulatory system. Amphibians and reptiles have closed and incomplete double circulation. Birds and mammals have closed and double circulation.

7-(c)

•  Open type blood vascular system is a type of circulatory system in which nutrients and waste are moved through the body with the help of a fluid which flows freely through the body cavity, rather than being contained in veins. Many invertebrates like insects (eg, cockroach) and shellfish have an open circulatory system, with the exact composition of the circulating fluid varying, depending on the animal species involved.
• The earthworm has a closed circulatory system.

• Insects have open type circulatory system.
• Amphibians and lizards have incomple double closed system.

8-(d) Incomplete double circulation is found in amphibians and reptiles. The left atrium receives oxygenated blood from the gills/lungs/skin and the right atrium gets the deoxygenated blood from other body parts. However, they get mixed up in the single ventricle which pumps out mixed blood

9-(d)

All of these

Reason: (i) Without any external stimuli, the nodal musculature has the ability to generate action potential. It is auto excitable.

(ii) Sinoatrial node (SA node) – pacemaker, which lies in the wall of right atrium near the opening of superior vena cava. The SA node is a mass of neuromuscular tissue.

(iii) Another mass of neuromuscular tissue, the atrioventricular node (AV node) is situated in the wall of the right atrium. The AV node picks up the wave of contraction propagated by SA node.

(iv) The AV node picks up the wave of contraction propagated by SA node. A mass of specialized fibers, the bundle of his, originates from the AV node. The bundle of his divides into two branches, one going to each ventricle.

(v) When the wave of contraction originating from the sinoatrial node reaches the atrioventricular node (AV node – pace setter), the latter is stimulated and excitatory impulses are rapidly transmitted from it to all parts of the ventricles to contract simultaneously. The ventricles force blood through long system of arteries and hence must exert great pressure on the blood.

10-(c) Nodal tissues are specialized cardiac musculature present in heart wall. This tissue has two patchesone present in the right upper corner of right atrium (SA node) & other is seen in the lower left corner of right atrium close to the atrio-ventricular septum (AV node). A set of specialized muscle strands which originates in the AV node and pass downwards in the interventricular septum is called Purkinje fibres.