How many combinations of genotypes are possible for the coat coloration of rabbits which is governed by three alleles?

a) 3 b) 6 c) 9 d) 12

b) 6

Explanation:

There are three different alleles (A,B,C) which are responsible for coat coloration but only combination of two can move forward because there are two loci at every homologous pair of chromosomes.

Thus, six combinations can be formed as AA, AB, AC, BB, BC, CC.

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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