Jello is a colloid, a semi-rigid structure i.e, semi-solid suspended in a liquid. When you Heat it up a bit and you'll break the protein bonds of the gelatin and it will liquefy completely and if you freeze, it becomes solid.
Plantain plant is a herb, because it does not have an aerial stem - what appears as a stem is really the leaves with sheathing bases. As the piant lives for several years it is called perennial herb