Which respiratory volume is excluded while calculating vital capacity?

A. Calcium: Calcium reabsorption primarily occurs in the distal convoluted tubule, not the loop of Henle.

B. Drugs: Drug secretion mainly happens in the proximal convoluted tubule.

C. Urea: Urea is secreted by the loop of Henle, especially in the thin descending limb, as part of the concentration of urine.

D. Bicarbonate ions: Bicarbonate is reabsorbed mainly in the proximal convoluted tubule, not secreted by the loop of Henle.

A. There are two secondary bronchi in the right lung and three in the left lung: There are three secondary bronchi in the right lung and two in the left lung due to the number of lobes in each lung.

B. The right primary bronchus is more vertical and wider than the left: The right bronchus is more vertical and wider, making foreign objects more likely to enter the right lung.

C. The carina is only present in the left primary branches: The carina is located at the bifurcation of the trachea into the right and left bronchi, not just in the left.

D. Inhaled air does not enter the terminal bronchioles: Inhaled air flows all the way through the bronchial tree, including the terminal bronchioles.