The isotope silicon-32 decays into phosphorus-32. silicon-32 has a half-life of 170 years and can be used to find the age of rocks it is contained in. which two statements are true regarding this scenario? pick two a) silicon-32 is the stable daughter isotope and phosphorous-32 is the unstable parent isotope. b) in a given rock sample, the amount of silicon-32 isotope gets divided in half about every 170 years. c) the half-life can be used to determine the amount of silicon-32 that has decayed from the time the closure temperature was reached. d) in a given rock sample, as the amount of silicon-32 lessens, so does the amount of phosphorous-32. e) in a given rock sample, the amount of silicon-32 is always equal to the amount of phosphorous-32.