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 lumbar
thoracic and lumbar
thoracic and sacral
cervical and sacral

Explanation:

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

Answer:

B. cervical and lumbar