Acid rain<span> is caused by a </span>chemical<span> reaction that begins when compounds like sulfur dioxide and nitrogen oxides are released into the air. These substances can rise very high into the atmosphere, where they mix and react with water, oxygen, and other </span>chemicals<span> to form more </span>acidic<span> pollutants, known as </span>acid rain<span>.</span>
Seafloor spreading occurs at divergent plate boundaries. As tectonic plates slowly move away from each other, heat from the mantle's convection currents makes the crust more plastic and less dense. The less-dense material rises, often forming a mountain or elevated area of the seafloor.
These are the following answers to the items
cell engulfs molecules in cell "drinking": pinocytosis<span>
molecules helped by protein; move insoluble molecules across plasma membrane: </span>facilitated diffusion
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molecules move in and out freely from high to low concentration: </span>passive diffusion
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cell engulfs microorganisms in cell "eating": </span>phagocytosis<span>
molecules "pumped" in or out from low to high concentration: </span>active transport<span>
oxygen, carbon dioxide: </span>passive diffusion<span>
transports sodium, potassium: </span>active transport<span>
transports glucose, amino acids: </span>pinocytosis
En las arqueas, generalmente se encuentra en la forma L-isomérica, mientras que las bacterias y eucariotas tienen la forma D-isomérica. Una segunda diferencia es la presencia de un enlace éter en oposición a los lípidos enlazados a éster que se encuentran en eubacterias y eucariotas.
