For me it seems that there is no test question,
Independent Variable: number of flowers.
Dependent Variable: different types of plants.
Control Variable: records
(b) a velocidade média para cada metade da viagem
A physical change does not change what the substance is. The type of change that changes the substance is the chemical change because in this process, chemical composition of the material changes, resulting to different properties. In physical change, the chemical composition of the material remains the same. An example is cutting a piece of paper. It only changes it physical appearance but the chemical composition of uncut paper is just the same with the cut one.