Bright-field microscopes are used for most microscopic work. true or false?

The correct answer will be option-true

Explanation:

A bright-field microscope is an optical instrument widely used by students and researchers all over the world.

The bright-field microscope is a compound light microscope which uses the light to see the samples. In the microscope the samples appear darker in color on the bright or light-coloured background.  This enables the viewer to clearly see the sample in the microscope.

Thus, true is the correct answer.

the answer that best describes the relative refractory period in the neuron is the resting membrane potential is restored, but concentrations of sodium and potassium are not restored to their original state.

the refractory period is the time during which another stimulus given to the neuron will not lead to a second potential. thus, because na+ channels are inactivated during this time, additional depolarizing stimuli do not lead to new action potentials.  

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a unit of heredity that is transferred from a parent to offspring and is held to determine some characteristic of the offspring.