(a)[3]
Name the two circulations in the mammalian double circulatory system, together with the main vein that returns deoxygenated blood to the heart.
(b)[1]
In a closed circulation, blood remains inside vessels at all times. Name the blood vessel type that links capillaries to veins.
(c)[2]
On Fig. 1.1: add a label line and the letter L to show the artery that carries blood from the heart to the lungs; add a label line and the letter R to show the valve that closes when the right ventricle is in systole.
(d)[5]
Complete the passage that explains how hydrogencarbonate ions are produced by filling the spaces with the correct biological term and, in the bracketed spaces, the molecular formula for two of the terms.