Cell<span> differentiation is how generic embryonic </span>cells become specialized cells<span>. This occurs through a process called gene expression. Gene expression is the specific combination of genes that are turned on or off (expressed or repressed), and this is what dictates how a </span>cell<span> functions
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Glucagon acts on the receptors of the liver cell. The gpcr include a internal signaling in the cell following the heterotrimeric G-proteins dissociates. It activates a pathway that results in the breakdown of glycogen to glucose or the de novo synthesis of glucose in the cells.
<span>Cretaceous
</span>Angiosperms evolved during the late Cretaceous<span> Period, about 125-100 million years ago.</span>
Alfred Russel Wallace, a biologist, naturalist and anthropologist who studied life in the tropics of Indonesia came up with the same idea of natural selection as Charles Darwin and prompted Darwin to publish his Origin of Specie sooner rather than later. He also studied the geographic distribution of species and as as well he was a social activist who criticized capitalism and warned of damage to the environment from man's economic activities.
