Traditionally, some textbooks from the United States used a system of six kingdoms (Animalia, Plantae, Fungi, Protista, Archaea/Archaeabacteria, and Bacteria/Eubacteria) while textbooks in Great Britain, India, Australia, Latin America and other countries used five kingdoms (Animalia, Plantae, Fungi, Protista and Monera).
For other uses, see Placebo (disambiguation) and Placebo effect (disambiguation). The placebo effect can be produced by inert tablets, by sham surgery, and by false information, such as when electrical stimulation is turned off in those with Parkinson's disease implanted brain electrodes.
Some women skip their periods because when they get to the placebo pills at the end of the package, they simply don't bleed. Other women skip their period purposefully by passing over the placebo pills and continuously taking hormone-containing pills.