Land plants are key components of the water cycle and several other biogeochemical cycles. It is involved in the regulation of the estrous and menstrual female reproductive cycles. This produces a positive feedback for changes induced by other processes such as orbital cycles. Interrupt latency is constant at three instruction cycles. These fluctuations express themselves as the observed business cycles. Lower latitudes correlate with longer life cycles. It is capable of tracking women's menstrual cycles. Mammary glands develop during different growth cycles. Their fluctuations correlate with Precambrian supercontinent cycles. Puberty coincides with the beginning of estrous cycles. This frequency is equal to 2 cycles per second. It is possible to predict other eclipses using eclipse cycles. Transmission may continue for any number of clock cycles. Both are valuable for their long historical records covering multiple solar cycles. Trematodes have a large variation of forms throughout their life cycles.