Fill in the missing letters in the paragraph.
The number of underlines shows how many letters you need to fill in. You may answer with the full word or only the missing part.

Living organisms survive by maintaining internal sta _ _ _ _ _ _ despite external change. This ability, known as homeostasis, allows biological systems to regulate var _ _ _ _ _ _ such as temperature, pH, and fluid balance within narrow limits. When these conditions dev _ _ _ _ from optimal levels, feedback mechanisms are activated to restore equilibrium. Such regulatory processes r _ _ _ on precise signaling between cells and organs. Disruptions in these systems can lead to disease, illustrating that homeostasis is not a passive state but an ac _ _ _ _ process that requires constant adjustment in re _ _ _ _ _ _ to environmental and phys _ _ _ _ _ _ _ _ _ demands.