Question

Choose the two half-reactions from a table of standard reduction potentials that most closely approximate the reaction that occur within the battery. What is the standard voltage generated by a cell operating with these half-reactions?
2Li(s) + Ag2CrO4(s) --------> Li2CrO4(s) + 2Ag(s)
Calculate the voltage at body temperature, 37°C

Answer 1

From the limited description you give I would pick
Li ==> Li^+ + e and
Ag^+ + e ==> Ag

You mention "the" battery so the use of the battery and the other conditions not listed may affect the results.
For the second part,
Ecell = Eocell - (RT/nF)ln Q
and you plug in T = 37 C but change that to kelvin. R is 8.314 and F = 96,485. If you want to convert ln to log, that is 2.303*ln. Q is the reaction quotient.