Which statement accurately describes the relationship between the brain and addiction?

a. all drugs act on dopamine synapses in the same way.

b. the brain reacts to excessive dopamine levels by increasing the number of dopamine receptors.

c. a higher amount of addictive chemicals are needed to get the same high when fewer receptors are present.

d. normal activities produce heightened responses once receptors are reduced.

C. A higher amount of addictive chemicals are needed to get the same high when fewer receptors are present...

relative dating involves things like higher layers are most recent than rocks lower in the sequence. this can be extended to the known sequence of fossils. rocks containing rabbit fossils are later than those containing dinosaur fossils.  

absolute dating methods mainly use radioactive elements that have known rates of decay and produce recognizable products. for example potassium 40 decays to produce argon. once a rock has solidified the argon is trapped. by measuring the argon and potassium0 you can get an accurate number for the age.  

some other methods are good for archaeological ages. dendrochronology involves recognizing the sequence of tree rings. the orientation of magnetized particles in baked clay can be used to date a fire.

hope this .. .

i think the answer would be d