What is the best definition of homologous structures in biology?

Structures that look identical on the surface and perform the same function in different species.

Structures in different species that are similar because they were inherited from a common ancestor.

Structures that evolved independently in different species to solve similar environmental challenges.

Structures that have been lost over time due to changes in an organism's environment.

What is the primary reason scientists focus on identifying homologous structures when studying the evolutionary history of different species?

To determine how different environments can create identical-looking features.

To prove that all life on Earth will eventually evolve to look the same.

To find evidence of a shared common ancestor between the species.

To catalogue all the possible functions a particular limb can perform.

Their shared streamlined body shape.

The presence of a similar vertebral column structure.

The fact that dolphins nurse their young with milk.

A comparison of their DNA sequences.

As homologous structures, because they both serve the same primary function of flight.

As analogous structures, because they serve a similar function but did not originate from a common ancestor's wing.

As vestigial structures, because they have been modified significantly from their original form.

As evidence of a very recent common ancestor between bats and butterflies.