Which of the following describes the relationship of parasitism?

a. oxpecker birds eat parasitic ticks off the backs of zebras.

b. a tapeworm latches itself in the intestines of a rat, feeding off all the nutrients eaten by the rat.

c. a polar bear catches a seal for dinner.

d. birds feed off the insects that are strirred up as cattle moves through.

B bc the tapeworm is the only one being helped and the rat is suffering from the tapeworms doings

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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meiosis is the first to occur after the nuclei of opposite of opposite mating types fuse