Question

insert dashes where needed.
new dna evidence suggests that the kiwi a small, flightless bird found in new zealand is closely related to the enormous, extinct elephant bird.

Explanation:

Dashes are used here to set off a non-restrictive appositive phrase that provides extra, non-essential information about the kiwi. The phrase "a small, flightless bird found in New Zealand" adds descriptive details that are not required to identify the kiwi, so it should be framed with em dashes (or the given dash) to separate it from the main clause.

Answer:

New DNA evidence suggests that the kiwi — a small, flightless bird found in New Zealand — is closely related to the enormous, extinct elephant bird.