I think the answer is electron shell.
Answer:
Increase the amplitude by blowing with more force.
Explanation: I answered this.
D. 18 x 10^23 is the total number of atoms in 1.0 mole of CO2
the complete question in attached figure
Let
x------------------- > actual yield
y------------------- > theoretical yield
z------------------- > percent yield
we have that
z=x/y
we know
x=47 g
y=56 g
therefore
z=47/56=0.839 ---------------- > 83.9%
the answer is the option C 83.9%