Which deciduous tooth has two roots and five cusps?

• A. Upper deciduous canine
• B. Deciduous upper lateral incisor
• C. Deciduous lower first molar
• D. Lower deciduous second molar

Answer: (D)

In deciduous teeth, you identify a tooth by how many roots it has and how many cusps sit on its crown. Molars in particular show multiple roots and several cusps, and the combination of two roots with five cusps points to a specific tooth in the lower jaw.

The lower deciduous second molar is the one that has two roots and a crown with five cusps, which is a distinctive pattern among the options. The other teeth listed do not combine these two features—either they have a single root (like incisors and canines) or a different cusp arrangement—so they don’t match both criteria at the same time. Therefore, the lower deciduous second molar is the correct pick.