I think B would be the most reasonable answer, the steps all seem to make sense
3600 years.
Since 65% of the carbon-14 is remaining, we need to get the logarithm to base 2 of 0.65 to determine how many half lives have expired. So: log(0.65)/log(2) = -0.187086643/0.301029996 = -0.621488377
So we know that 0.621488377 half-lives has gone by to the bone sample. Now we just need to multiply by the half-life of carbon-14 which is 5730 years. So: 0.621488377 * 5730 = 3561.128399 years. Rounding to the nearest 100 years gives us 3600 years.
Answer:
The answer is "52.8".
Explanation:
Please find the graph file in the attachment.
They have the atoms in 8 corners with one unit cell in an one so mesh (SCC).
Atoms throughout the corner contribute 
to both the cell unit
Atom number per SCC unit cell, 
Let 'r' become the atom's radius. 
We can see from the diagram that edge length 
The outside has grass and trees
Fe(s)+Ca(NO₃)₂(aq)⇒no reaction
<h3>Further explanation</h3>
In voltaic series
Li-K-Ba-Ca-Na-Mg-Al-Mn- (H2O) -Zn-Cr-Fe-Cd-Co-Ni-Sn-Pb- (H) -Cu-Hg-Ag-Pt-Au
The more to the left, the metal is more reactive (easily release electrons) and the stronger reducing agent
The more to the right, the metal is less reactive (harder to release electrons) and the stronger oxidizing agent
So that the element located on the left can push the element on the right in the redox reaction
Reaction
Fe(s)+Ca(NO₃)₂(aq)⇒no reaction
Fe cannot reduce Ca because Ca is more reactive, so the reaction does not occur
On the contrary, this reaction can occur
3Ca(s) + 2Fe(NO₃)₃(aq) = 3Ca(NO₃)₂(aq) + 2Fe(s)
