Answer:
Direct proportionality
Step-by-step explanation:
The graph of variables that are directly proportional such as the temperature and volume of a gas has a graph consisting of a diagonal line that from the lower left of the graph to the upper right of the graph
According to Charles law, the volume of a given mass of gas is directly proportional to its temperature in Kelvin at constant pressure
Charles law can be represented mathematically as V ∝ T
From which we have;
V₁/T₁ = V₂/T₂, therefore, the graph of V to T has a constant slope, ΔV/ΔT.