What is the most important reason to control the conditions of an experiment?

What happens when the cell copies its chromosomes

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?

The negative change found inside the plasma membrane is created by potassium ions sodium ions hydrogen ions chlorine ions