Number of neutrons is 121.
Answer:
Option C. The same number of energy levels.
Explanation:
From the diagram given above, element (i) belong to group 2 while element (ii) belong to group 6.
Also, both element i and ii belong to the same period (i.e period 4). This simply means that both element i and ii have the same number of energy levels.
NOTE: Elements in the same period have the same number of shells of electrons which simply means they have the same energy levels.
Koalas are not crusty, but their fur is very coarse, like wool.
Hope this helps.
Answer : The
must be administered.
Solution :
As we are given that a vial containing radioactive selenium-75 has an activity of
.
As, 3.0 mCi radioactive selenium-75 present in 1 ml
So, 2.6 mCi radioactive selenium-75 present in 
Conversion :

Therefore, the
must be administered.
All the information is answered/given in the paragraph except that the study doesn’t show cells in their natural habitat!