1. list and explain the difference between the minimum voltage and maximum voltage achieve in a nerve impulse.

The minimum voltage is observed as the resting potential of the cell membrane. This has a value of -70 millivolts and exists when there is no stimulus present. After a stimulus is applied, the sodium-potassium channels allow the movement of ions in and out of the cell membrane. Before the channel is able to close again and restore itself to the resting potential, hyperpolarization occurs and a maximum voltage of about 30-40 millivolts is achieved. 

Because the earth is not round ,but it may seem round when viewed from ,our planet but true some points earth is not round was an oblate spheroid -a square that it squashed as globe however is not even a perfect oblate spheroid.in fact isaac newton's first proposed that earth was not perfectly round but it was an oblate spheroid instead.that mean a square that is squashed as its poles and swollen at the