I believe this is a double replacement. As you can see none of the chemical symbols are missing, there just "replaced".
Answer :
is the oxidizing agent and Fe is the reducing agent.
Explanation :
Reducing agent : It is defined as the agent which helps the other substance to reduce and itself gets oxidized. Thus, it will undergo oxidation reaction.
Oxidizing agent : It is defined as the agent which helps the other substance to oxidize and itself gets reduced. Thus, it will undergo reduction reaction.
The balanced redox reaction is :

The half oxidation-reduction reactions are:
Oxidation reaction : 
Reduction reaction : 
In order to balance the electrons, we multiply the oxidation reaction by 4 and reduction reaction by 3 then added both equation, we get the balanced redox reaction.
Oxidation reaction : 
Reduction reaction : 

In this reaction,
is the reducing agent that loses an electron to another chemical species in a redox chemical reaction and itself gets oxidized and
is the oxidizing agent that gain an electron to another chemical species in a redox chemical reaction and itself gets reduced.
Thus,
is the oxidizing agent and Fe is the reducing agent.
Answer: The age of the tool is 15539 years
Explanation:
Expression for rate law for first order kinetics is given by:
where,
k = rate constant
t = age of sample
a = let initial amount of the reactant = 100
a - x = amount left after decay process =
a) for completion of half life:
Half life is the amount of time taken by a radioactive material to decay to half of its original value.

b) for 15.5 % of original amount

Thus age of the tool is 15539 years
Evolved. the reason why is because mabye they got trapped or something in san francisco, and since they couldnt go back to japan, they had to evolve into san francisco in order to stay alive