An mRNA template is used to create a DNA strand.
When a specimen is to be observed under the light microscope, scientists usually stain the specimens using different type of chemical stains depending on the type of specimen to be observed. Staining of specimen make the structures that are to be observed in the specimen very visible under the microscope, this make it easy for scientists to observe their structures.
Since the cell is in a shoebox, we can assume this cell is a plant cell. the balloon most likely represents the vacuole, which is the largest organelle in the plant cell. the marbles could represent ribosomes, but ribosomes aren’t the only round organelle so i’m not sure about that one.