Instead of lungs, insects breathe with a network of tiny tubes called tracheae. Air enters the tubes through a row of holes along an insect’s abdomen. The air then diffuses down the blind-ended tracheae. Since the biggest bugs have the longest tracheae, they should need the most oxygen to be able to breathe.
Normally, there are 18 pairs of ribs in the horse, but a nineteenth rib on one side or both is not considered all that rare. Eight pairs of ribs are known as true ribs. They join the segments of the sternum or breastbone. The other 10 are known as floating ribs–merely overlapping and being attached to each other.
Pure water is not a good conductor of electricity. Ordinary distilled water in equilibrium with carbon dioxide of the air has a conductivity of about 10 x 10-6 W-1*m-1 (20 dS/m). Because the electrical current is transported by the ions in solution, the conductivity increases as the concentration of ions increases.