Answer:
The correct answer would be - All birds share a common ancestor.
Step-by-step explanation:
All birds shows similar characteristics and traits even though they belong to different species. According to the various studies and research it is found that the reason behind this similarity in traits and characteristics due to the common ancestor.
Studies states that the all modern birds share the common ancestor that was found during some time of Late Cretaceous and evolved from that common ancestor.
Thus, the correct answer is : All birds share a common ancestor.