In chemistry, the CONCENTRATION of a solution is the amount of a substance present within a volume of another substance. In other words, the concentration refers to the amount of a solute dissolved in a particular volume of a solvent to make a solution.
Concentration can be expressed in mass per volume i.e. g/cm³ or mol per volume i.e. mol/L or mol/dm³ etc. The amount of a substance is measured in Mass or mole, while the volume of a substance in Litres (L).
Plasmodesmata are microscopic channels which traverse the cell walls of plant cells and some algal cells, enabling transport and communication between them. This is the path that viruses use to spread throughout a plant's system.