Question

a. the bone cells of all these organisms have identical dna.
b. these species evolved at the same time.
c. the arms of these organisms are used for the same tasks.
d. these species have descended from a common ancestor.
e. their bone structures indicate anatomical homologies.

Explanation:

Homologous structures are anatomical features with similar bone organization but different functions, which indicate shared ancestry.

• A is incorrect: While related, their DNA is not identical.
• B is incorrect: These species evolved at different times.
• C is incorrect: The structures have different uses (e.g., human grasping, bat flying, dolphin swimming).
• D is correct: Homologous structures are evidence of descent from a common ancestor.
• E is correct: The matching bone layout defines anatomical homologies.

Answer:

D. These species have descended from a common ancestor.
E. Their bone structures indicate anatomical homologies.