- PowerScore Staff
- Posts: 947
- Joined: Oct 19, 2022
- Mon May 12, 2025 8:23 pm
#112867
Hi Let's,
It looks like you may be conflating two different ideas.
What is useful for land dwelling vertebrates is having "rotating limbs terminating in digits, a characteristic useful for land movement" (and, by extension, useful for survival on land). The Ancanthostega had this characteristic even though it was exclusively aquatic.
These two facts provide the support for Answer E.
The fact that the skeleton of the Ancanthostega was too feeble for land movement is a completely separate issue. That does not mean that having "rotating limbs terminating in digits" (e.g. arms, hands, fingers, legs, feet, toes) would not be useful for land survival in other animals that have stronger skeletons.
It looks like you may be conflating two different ideas.
What is useful for land dwelling vertebrates is having "rotating limbs terminating in digits, a characteristic useful for land movement" (and, by extension, useful for survival on land). The Ancanthostega had this characteristic even though it was exclusively aquatic.
These two facts provide the support for Answer E.
The fact that the skeleton of the Ancanthostega was too feeble for land movement is a completely separate issue. That does not mean that having "rotating limbs terminating in digits" (e.g. arms, hands, fingers, legs, feet, toes) would not be useful for land survival in other animals that have stronger skeletons.