A scientist wants to determine the age of a rock. The rock contains an index fossil and an ancient relative of a living organism. Which is more useful for dating the rock, and why?

an ancient relative of a living organism would be more useful for dating the rock because fossils in a rock layer represent what lived during the period the rock was deposited.

Ancient Relative of a living organism

Explanation: Ancient Relative because by using the index fossil, you are also using the law of superposition. This law does not give you an accurate/specific date but instead the order they are in (i.e me saying i am older than my siblings compared to me saying i am 2 years older than them). By using an ancient relative of a living thing then we can see its phylogenic tree and measure around how old it is. Fossils also hold carbon and chemicals in there bones which allows us to use carbon dating. Carbon dating is an accurate way of measuring age.

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.  

read more on -

few emissions (dabs bc im right)