What is the role of myelin in neurons? a. to change the direction that na+ and k+ move through ion channels during the action potential. b. to increase the speed that action potentials travel down the neuron. c. to prevent the neuron from generating action potentials. d. to cause multiple sclerosis when present and intact, as it blocks action potential movement and must be removed by the immune system.

In cattle a single gene with two alleles determines fur color the fur can be red white or roan roan fur has both red and white hair which of the following statements is true a the allele for roan fur color is dominant over red and white fur color b the allele for red fur color is dominant over white and roan fur color c the roan and white alleles are expressed independently of the other d the red and white alleles are expressed independently of each other