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.
Hookeâs Law is a principle of physics that states that the that the force needed to extend or compress a spring by some distance is proportional to that distance. The law is named after 17th century British physicist Robert Hooke, who sought to demonstrate the relationship between the forces applied to a spring and its elasticity. 1  Illustration of Hookeâs Law, showing the relationship between force and distance when applied to a spring.