gene flow natural selection genetic drift mutation
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: A population of tree-climbing lizard lives on one bank of a large river. The other bank of the river is a treeless prairie. During a flood, 40 lizards were transferred to the prairie side of the river. After 200 generations, this transferred population of lizard lost the ability to climb.Which mechanism is most likely responsible for this loss of function within the transferred population?
Possibilities:
- gene flow
- natural selection
- genetic drift
- mutation

genetic drift