Question

despite having wings, ostriches are a flightless bird species. scientists once believed that their wings were vestigial, meaning theyre leftover from an earlier stage of evolution and dont have a current function. however, a study by nina u. schaller and colleagues found that ostriches use their wings for stability during running, to help them maneuver and brake at high speeds. additional research has shown that ostriches spread their wings to regulate their body temperature, and that male ostriches use their wings in courtship dances. these findings suggest that ostrich wings ______
which choice most logically completes the text?
choose 1 answer:
a are used solely for defense against predators.
b have no functional purpose, confirming scientists assumption.
c are not vestigial, as previously thought.
d limit the ostrichs ability to run efficiently.

Explanation:

The text first mentions that scientists once thought ostrich wings were vestigial (no current function). Then it presents research showing they have functions like aiding running, temperature regulation, and courtship. So the conclusion should counter the vestigial idea.

• Option A: The text doesn't mention defense against predators as the sole use.
• Option B: Contradicts the research findings which show functions.
• Option C: Correct as the new research shows they have functions, so not vestigial as previously thought.
• Option D: The text says wings help with running (stability, maneuvering), not limit it.

Answer:

C. are not vestigial, as previously thought.