18. explain how clearing forests by cutting and burning trees contributes to climate change.
weather patterns change as a result of changes in forest patterns, which lead to climate change.
reducing the number of trees reduces the amount of shade, which leads to higher local temperatures.
clearing forests leads to large areas of bare ground that absorb more light energy from the sun than forested areas.
burning trees releases huge amounts of carbon dioxide, which is a greenhouse gas.

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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this is true, assuming that the allele is completely recessive and incomplete dominance is not a factor.