Question

tunicates and hydras have fewer similarities in their fgfr gene sequences than tunicates and ribbed newts have. this piece of evidence supports the following claim:
tunicates share a more recent common ancestor with ribbed newts than with hydras.
which additional piece of evidence best supports the same claim?
tunicate larvae have a hollow nerve cord along the back that is absorbed during metamorphosis to adults. ribbed newts have a hollow nerve cord along the back throughout all life stages. hydras have a decentralized nerve net.
tunicate adults are filter feeders that are typically attached to substrate on the ocean floor. ribbed newts are active predators throughout life, mostly eating small invertebrates. hydras are sit - and - wait predators that attach to substrate or free - float in ponds and catch tiny invertebrates that touch their tentacles.
tunicates live exclusively in the ocean. ribbed newt larvae live exclusively in freshwater, breathing through external gills, but can spend time on land after metamorphosis. hydras live exclusively in freshwater.

Explanation:

The claim is about evolutionary relationships. The first piece of evidence is genetic (FGFR gene sequences). To support the claim further, anatomical evidence (nerve cord structure) is relevant. Tunicate larvae and ribbed newts have a hollow nerve cord (a chordate feature), while hydras have a decentralized nerve net. This anatomical similarity (hollow nerve cord in tunicate larvae and ribbed newts) reinforces the idea of a closer evolutionary relationship (more recent common ancestor) between tunicates and ribbed newts compared to tunicates and hydras. The other options (feeding habits and habitat) are ecological and less indicative of evolutionary relatedness compared to anatomical/genetic features.

Answer:

Tunicate larvae have a hollow nerve cord along the back that is absorbed during metamorphosis to adults. Ribbed newts have a hollow nerve cord along the back throughout all life stages. Hydras have a decentralized nerve net.