Question

question 5(multiple choice worth 3 points)
(05 01 mc)
a platypus is classified as a mammal because it has fur and feeds its offspring milk, yet it lays eggs, which is uncommon for mammals but not for other vertebrates. which of the following pieces of evidence would be most helpful in strengthening the case for continuing to classify it with the mammals?
evidence that all vertebrates share a common ancestor
evidence that some platypuses have evolved to bear live young under certain circumstances
fossil evidence of platypuses living alongside other ancient mammals
dna evidence showing it was more closely related to mammals than to other vertebrates

Explanation:

• Evidence that all vertebrates share a common ancestor: This is too broad. All vertebrates (including non - mammals like fish, reptiles) share a common ancestor. It doesn't specifically strengthen the platypus - mammal link.
• Evidence that some platypuses have evolved to bear live young under certain circumstances: This is a single, perhaps rare, observation. It may not be a strong, generalizable piece of evidence for classification.
• Fossil evidence of platypuses living alongside other ancient mammals: Just living in the same time and place as other mammals doesn't necessarily mean they are closely related. They could have co - existed without a close evolutionary relationship.
• DNA evidence showing it was more closely related to mammals than to other vertebrates: DNA is the blueprint of life. If the platypus' DNA shows a closer relationship to mammals (based on genetic sequences, gene arrangements etc.) than to other vertebrates (like birds, reptiles), it provides strong, fundamental evidence for its classification with mammals. Genetic relatedness is a key factor in modern biological classification.

Answer:

DNA evidence showing it was more closely related to mammals than to other vertebrates.