A fern is a member of a group of approximately 12,000 species of vascular plants that reproduce via spores and have neither seeds nor flowers.They differ from mosses by being vascular (i.e. having water-conducting vessels). They have stems and leaves, like other vascular plants.ost ferns have what are called fiddleheads that expand into fronds, which are each delicately divided. Leptosporangiate ferns (sometimes called true ferns) are by far the largest group, but ferns as defined here (ferns sensu lato) include horsetails, whisk ferns, marattioid ferns, and ophioglossoid ferns.
The density of H 2 O at 39.8 Â°C is 0.992 g/mL. Solution. Raoult's Law can be used to express the vapor pressure relationships of solutions containing both volatile and nonvolatile solvents. Raoult's Law is expressed by. P solution = Ï solvent P 0 solvent where. P solution is the vapor pressure of the solution.
Darcy's law is a phenomenologically derived constitutive equation that describes the flow of a fluid through a porous medium. The law was formulated by Henry Darcy based on the results of experiments on the flow of water through beds of sand.ne application of Darcy's law is to water flow through an aquifer; Darcy's law along with the equation of conservation of mass are equivalent to the groundwater flow equation, one of the basic relationships of hydrogeology. Darcy's law is also used to describe oil, water, and gas flows through petroleum reservoirs.