Experimental technique I believe
The building blocks of protein are C. AMINO ACIDS.
Amino acids are made up of a center carbon atom bound positively to a charged amino group and a negatively charged carboxyl group and a side chain.
The primary structure of a protein is the sequence of an amino acids that are attached together by a peptide bond
The secondary structure of a protein, the polypeptide is folded through the mechanisms of amino acids rotating around bonds folding into a helix or a pleated sheet structure and stabilized by a hydrogen bond.
Answer;
-Helium atom
Explanation;
-An alpha particle is identical to the nucleus of a helium atom.
-Alpha particle is one type of particles emitted during a radioactive decay, others being gamma and beta particles. Alpha particles are produced during the process of alpha decay.
-When an alpha particle is generated during a radioactive decay, the mass number of the radioactive particle increases by 2 while the atomic number increases by 4.