WAEC Biology 2018 Papers

Concept:A dental formula shows the number of each type of tooth in one half of the upper and lower jaws of an animal.Explanation:Rabbits are herbivores with a characteristic dentition.They have two pairs of upper incisors and one pair of lower incisors, so the incisor ratio is $I \frac{2}{1}$.Rabbits have no canines at all, hence $C \frac{0}{0}$.Their premolar ratio is $P \frac{3}{2}$ and their molar ratio is $M \frac{3}{3}$.So the complete dental formula is $I \frac{2}{1}$ $C \frac{0}{0}$ $P \frac{3}{2}$ $M \frac{3}{3}$.This gives a total of $2(2+1+0+0+3+2+3+3) = 28$ teeth.Comparing with the options, this formula matches option A.Answer:A. $I \frac{2}{1}$ $C \frac{0}{0}$ $P \frac{3}{2}$ $M \frac{3}{3}$