The molecular mechanisms that underlie this process are controversial. This action allows the chemical mechanisms that underlie human vision and plant photosynthesis. These connections provide the structure for the neural circuits that underlie reflexes. Four principles are posited to underlie social stratification. Similar processes could underlie belief perseverance. Impairment of Purkinje synapses is a component of cerebellar degradation that could underlie essential tremor. Cellular changes generally underlie alterations in cardiac structure. They are crucial to the biological computations that underlie perception and thought. This suggests some shared genetic pathology may underlie all four diseases. A larger number of factors may underlie these five factors. Laboratory studies suggest that an imbalance between these chemicals may underlie myoclonus. Mountain formation refers to the geological processes that underlie the formation of mountains. Michels stressed several factors that underlie the Iron Law of Oligarchy. Group theoretic arguments therefore underlie parts of the theory of those entities. Deficiencies in DNA repair underlie many forms of cancer.