Answer:
Natural selection
Step-by-step explanation:
Natural selection is the mechanism of evolution in which organisms evolve in order to adapt the changes in the habitat for their survival. Living organisms are naturally variable and adjust themselves according to their surroundings.
In the given example, bats in Texas evolve themselves with longer hang claws to adapt the rocky nature of the surrounding. These longer hang claws provide them the ability to cling to the rock, which is an adaptive feature of bats that is influenced by the environment.
Hence, the correct option is "Natural selection".