The differentiation is based on a set of activation / inactivation of genes (parts of DNA) via complex cascades of regulation. We can not consider a differentiating cell individually. Indeed, its "expression profile" depends on its environment: cell-cell interactions, cell-matrix. It is these extra-cellular signals that will trigger the internal regulation signals. The establishment of plans for the organization of a Drosophila embryo or the development of limb buds in mice are well-known models. In these models, so-called "positional" information plays a large role: a substance present in the form of a concentration gradient in the extracellular medium will trigger or not intracellular signals depending on the dose at which the cells are exposed along this gradient.
Answer: B
Explanation: Because inside of the bottle when the bottle is tipped upside down the friction from the water going against the walls should push it down.
A plant cell would have cell walls while an animal sell would not.
The red blood cell lives for up to about 120 days.
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