" Would natural selection be seen as one of the evolutionary processes that affected the physical features of Neanderthals (explain your answer briefly)? What is the speculation as to how the environment affected the physical features of Neanderthals?"

yes natural selection was one of the evolutionary process

Explanation:

The Neanderthals under went Natural selection process in their evolutionary process in regards to their physical features as seen in their growing of hairs around their body to protect them from severe cold conditions that they experience and live in. also they developed stronger bodies as to enable them live in caves and rocks

through natural selection process Neanderthals have developed physical features that make scientist believe they are closer to the human specie or belong to the Homo sapience and these physical features they developed where due to the Natural environment they found themselves  ( natural selection process)