Assertion   :       Heart valves resemble swing doors in action.

Reason      :       Valves are present in the heart chamber, at the opening of the heart into large arteries and veins.

1. If both the assertion and the reason are true and the reason is a correct explanation of the assertion
2. If both the assertion and reason are true but the reason is not a correct explanation of the assertion
3. If the assertion is true but the reason is false
4. If both the assertion and reason are false

Assertion     :  Closed circulatory system is more effective than open type.

Reason        :  The closed circulatory system considerably enhances the speed, precision and efficiency of circulation.

Assertion   :       Cardiac output rises during exercise.

Reason      :       Cardiac output helps in less oxygen consumption.

Assertion    :       EEG is of immense diagnostic value in the cardiac diseases.

Reason      :       Defects in cardiac functions can be reflected in changes in the pattern of electrical potentials recorded in the EEG. 

Assertion   :       An artificial pacemaker can replace the sinoatrial node of heart.

Reason      :       This is because, an artificial pacemaker is capable of stimulating the heart electrically to maintain its beats.

Assertion   :       Mixing of oxygenated and deoxygenated blood occurs in reptilian and amphibian hearts.

Reason      :       This happens because of the incomplete partitioning of the auricle.

Assertion   :       Left ventricle of heart has a thinner wall than that of the right ventricle.

Reason      :       Left ventricle needs to pump blood to nearby lungs only.

Assertion   :       Heart of fish contains only deoxygenated blood.

Reason      :       Oxygenated blood do not return back to the heart in fishes.

Assertion   :       Blood flows at a very slow velocity in the lacunae and sinuses of prawn.

Reason      :       This happens because of the absence of heart in the prawn.

Assertion   :       The increased permeability of the lymph capillaries is easily altered.

Reason      :       The increased permeability of the capillary walls leads to oedema or swelling.