I don’t know what exactly is but see at the picture.
I know for certain, that chloroplast does not belong on that list, chloroplast only belongs inside of plant cells to produce energy required for the plant. I am not sure about the era or er, but chloroplast does not belong.
Hope this helps, if not, comment below please!
Answer:
a) Sm
Explanation:
Hello,
This substantiation could be done by knowing how to compute the released energy for 1 mol the oxide. Thus, for Sm, the computation turns out into:

The sign just indicates that the heat is released due to the chemical reaction and it matches with the indicated heat in the statement.
Best regards.
The question is incomplete, the complete question is shown in the image attached to this answer.
Answer:
a) Br^-
b) FeCl3
c) slower
d) see the first attached image
Explanation:
Aromatic compounds undergo electrophilic substitution sections in the presence of the appropriate electrophile.
In the reaction above, the Br^- nucleophile attacks the Lewis acid FeCl3. Recall that the nitro group is meta directing hence the incoming Br^+ electrophile is directed towards the meta position as shown in the image attached.
Note that the nitro group deactivates the ring towards electrophilic substitution hence the reaction is slower with nitrobenzene than with unsubstituted benzene.