6) The first step in the decay series of 238U (238U to 234Th) has a half-life of 4.51 x 10'yr. 238U -> 234 Th
+ bX
for a, -18, y, and +18 type in the actual words alpha, beta, gamma and positron or the element
with the mass number (e. g. "Carbon-12")

B? i feel like this is a trick  

Answerthe half-reaction having the greatest tendency to occur at the anode:     i₂(aq) + 2e⁻  ⇄ 2i⁻  ;   e = +0.53 v======oxidation occurs at the anode. we must therefore find the half-reaction with the greatest tendency to oxidize.the given values of e are reduction potentials (the form of the half-reactions are of reduction).the lower the reduction potential, the higher the potential to oxidize. the half-cell with the lowest reduction potential will have the greatest tendency to oxidize at the anode.the half-reaction having the greatest tendency must be    i₂(aq) + 2e⁻  ⇄ 2i⁻    e = +0.53 vbecause its reduction potential is the lowest out of the three.

It is a ok  i know i have a brain functioning well.                                                                                                                                                           

The percentage of the rock record is 66%plz mark me brainliest! hope this !