Directly Proportional - GCSE Biology Definition

"Directly proportional" is a term used to describe a relationship between two variables in which they increase or decrease at the same rate. In GCSE Biology, this means that if one value goes up, the other one goes up too, and if one goes down, the other does the same. For example, when looking at how plants grow, if the amount of sunlight the plant receives is directly proportional to its growth, then doubling the sunlight will double the growth of the plant, assuming all other conditions remain the same. This concept helps us understand how changes in one factor can lead to changes in another.