I think the answer is (1) Co. Because the element of Cobalt also has 2 electrons at the outer layer which is the same as Calcium. And the outer layer is an important factor which can affect the property of an element.
The amino acids are the molecules where we can found the carboxyl group (-
), amino group (-
), hydrogen atom (H) and a residual R-group. On the structure of the residual R-group the name of the amino acid depends. Like if R is hydrogen (H) the amino acid is alanine; If R- group is a phenyl group i.e. 
, the compound is called phenyl alanine. The structure of the general amino acid skeleton can be shown as-
Field or discipline
hope it helped
Answer:
A disadvantage is pharmaceuticals
Explanation:
