Which is an example of a specific immune response to a pathogen?

Ricardo notices that when he plays soccer in the rain, his ball does not seem to go as far after a kick. what is the best scientific question that ricardo could ask about this observation? is soccer better played in the rain or sun? how does rain affect the distance a soccer ball can travel? how does rain affect the speed of a soccer ball? is soccer affected by the rain?

Which is an example of a population?

When analyzing tree rings, what do scientists assume a thin ring indicates?