Question

is the group of words in bold a phrase or a clause?
the cranium, a grouping of eight bones fused together, forms the top portion of the skull and functions like a protective helmet for the brain.
phrase clause

Explanation:

A phrase is a group of words without a subject - verb relationship, while a clause has a subject and a verb. The bolded group “like a protective helmet for the brain” has no subject - verb combination, so it is a phrase.

Answer:

phrase