These macromolecules are polar [polar: having different ends] because they are formed by head to tail condensation of polar monomers. Let's look at the three major classes of macromolecules to see how this works, and let's begin with carbohydrates.
Bostwick Steel Lath Company advertisement for steel truss loop type metal lath in 1920. A lath or slat is a thin, narrow strip of straight-grained wood used under roof shingles or tiles, on lath and plaster walls and ceilings to hold plaster, and in lattice and trellis work.
Heavy rust often accompanies pits in metal. To fix pitted metal, whether it is a fender, picture frame or decorative item for your garden, head to an auto parts store.Pits in metal are more than unattractive, this corrosion can weaken the metal.. Sand the metal and hardened filler with a sanding block and 80-grit sandpaper, if necessary, and wipe off the dust with a dry rag. Sanding with coarse sandpaper is only necessary if you were unable to scrape off the excess filler evenly, which leaves ridges and bumps of filler on the metal.