Question

is the group of words in bold a phrase or a clause? lightning, which never occurs without a thunderstorm, contains one hundred million to one billion volts of electricity. phrase clause

Explanation:

A phrase is a group of words without a subject - verb combination. A clause has a subject and a verb. "contains one hundred million to one billion volts of electricity" has the subject "Lightning" (even though it's before the bold - part, it's what is doing the "containing") and the verb "contains". So it's a clause.

Answer:

clause