Question

the chapter story demonstrated how paleontologists carefully compared the bones of indohyus, an extinct mammal, to more modern mammals to test hypotheses about its evolutionary relationships. one such hypothesis was that indohyus had some adaptations related to a possible aquatic lifestyle. we know that water - dwelling mammals often share the adaptive trait of thickened bones. examine the cross sections of bones and click the bones that most likely belong to aquatic mammals. click or tap the appropriate places in the image.

Explanation:

Aquatic mammals have thick - ened bones. Look for cross - sections with relatively thick bone walls.

Answer:

The bone with the thickest outer layer among the images is likely from an aquatic mammal. (Since no specific clickable elements are numbered or named, a general description is given based on the principle of thickened bones.)