If 1 g of Californium-251 has decayed from a sample that was originally 2 g, how old is the sample?

dopamine..

"it was found that some people who were taking the drug l-dopa to raise their levels of dopamine were developing schizophrenic-like symptoms supporting research a strength of the dopamine hypothesis is that there are many studies which have shown support for the neurochemical explanation."

an energy transformation flow diagram is shown

where is it ?

when heated, the valance electrons increased their speed and transferred the heat from electron to electron.   i just took the test.