Final answer:
The two functions of fontanels in a baby's skull are flexibility during childbirth, allowing the baby's head to pass through the birth canal, and providing space for brain growth and skull expansion after birth.
Step-by-step explanation:
The two functions of the fontanels in a baby's skull are c) Flexibility during childbirth and brain growth. The fontanels, often referred to as 'soft spots,' are broad areas of fibrous connective tissue that allow the bony plates of the skull to move and overlap during the birthing process, which aids the baby's head in passing through the birth canal. Post-birth, the fontanels facilitate the continuous growth of the skull and the enlargement of the brain.
This growth happens because fontanelles are not yet ossified at birth and constitute a flexible membrane that can expand and allow the brain to grow. Eventually, these fontanelles close as the bones ossify and form suture lines, which typically disappear by age 2 in a process known as synostosis, where the connective tissue hardens to form the skull.