What is the half life of each of these radioactive isotopes?
a radioactive isotope decreased to one-fourth its original amount in 18 months.

Me to solve all the questions on the sheet attached

1) sections 1, 2, and 10 are significant primarily because they suggest the likelihood that a) widow wycherly is actually the woman in the full-length portrait. b) dr. heidegger wants to include his guests in an experiment with the water. c) dr. heidegger plans to drink some of the water from the vase and needs witnesses. d) the guests will be asked to witness dr. heidegger's transformation when he drinks the water.

In a system, when potential energy decreases, then entropy also decreases. true false