Action potentials (nerve impulses) are changes in the membrane potential that, once started, will affect the entire excitable membrane. the first action potential is usually generated at the initial segment of the neuron's axon. this activity will test your understanding of the sequence of events that occur at the membrane of the initial segment of the axon during generation of an action potential. place the events involved in generation of an action potential in the correct order of occurrence from left to right. 1.k+ effluxrepolarization2.na+ channels closek+ channels open3.hyperpolarization k+ channels close4.threshold stimulus na+ channels open5.na+ influx depolarization

americans began to notice growing differences between the northern and southern sections of the country. there were more people living in cities in the north, which made it more urban. more people lived on farms in the south, which made it more rural. while many people were farmers in the northern states, there were now other ways to make a living, such as working in mechanical cotton gins factories manufacturing cloth, tools and other goods. people in the north supported high tariffs on goods imported from europe because the extra cost encouraged people to “buy american” instead. in the southern states, planters did not like tariffs because they sold most of their production to europe and bought their tools from there as well. southerners believed the protective tariff was something that only northern factory owners keep their profits high. so the southern politicians came up with an idea. they would opt out. they would simply ignore the protective tariff. it was ‘null and void’ in south carolina. the state would not collect the taxes on goods imported into south carolina, no matter what the president said they had to do. this decision led to the nullification crisis.

the answer is: metamorphic rocks often show the presence of fossils, also a

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-lavira: )