To determine which cross section of the graph shows the chipmunks that are most likely to survive and reproduce due to natural selection, you would need to consider the characteristics of the chipmunks represented in each cross section. Typically, in the context of natural selection, you would look for traits that confer advantages, such as better adaptation to the environment, increased reproductive success, or greater resilience to threats.
Without having the visual graph to reference, I can't give a specific answer related to the cross sections. However, generally, the cross section that shows the most favorable traits for survival in the given environment would be the answer you are looking for.
Please analyze the traits shown in each cross section, and choose the one that reflects the adaptation that leads to higher survival and reproduction rates. If you provide more details about the specific traits in each section, I can help you reason through it!