Question

the four curves of the adult spinal column are not all present at birth. which of the following are the secondary curves?
sacral and lumbar
cervical and sacral
cervical and lumbar
thoracic and lumbar
thoracic and sacral

Explanation:

At birth, the thoracic and sacral curves are present (primary curves). The cervical curve develops as an infant begins to lift its head (around 3 - 4 months) and the lumbar curve develops as the child begins to walk (around 12 - 18 months). These are secondary curves.

Answer:

cervical and lumbar