Girth (tack) place, other pieces of equipment are also used in jumping or speed sports such as polo, eventing, show jumping, and fox hunting; or on rough terrain such as trail riding. These include breastplates, overgirths, cruppers, and, on pack saddles, breeching. Studies have shown that, although girths may restrict the movement of the ribcage in the horse, they have no effect on the horse's ability to take in air. Several types of girth are shaped to allow ample room for the elbows. The Balding style is a flat piece of leather cut into three strips which are crossed and folded in
Animal testing on frogs which reaches its reproductive age in five months rather than one to two years (as in "X. laevis"), facilitating faster studies across generations. The genome sequence of "X. tropicalis" was scheduled to be completed by 2015 at the latest. Frogs are widely used in classroom dissections and teaching exercises. Animal testing on frogs Frogs have been used in animal tests throughout the history of biomedical science. Eighteenth-century biologist Luigi Galvani discovered the link between electricity and the nervous system through studying frogs. The African clawed frog or platanna, "Xenopus laevis", was first widely used in laboratories in pregnancy assays in