Answer:
The correct answer will be amino acids.
Step-by-step explanation:
The process of protein synthesis takes place in an organelle called ribosomes. The ribosome reads the information coded in the mRNA in the form of triplets of nitrogenous bases also known as "codons". The codons code for specific amino acids which are assembled or joined via peptide bonds in the ribosomes.
In the question, Katie wanted to make doghouse of the wood and nails in which if doghouse represents the protein, the nails and wood will represent the basic unit or monomer of a protein called amino acids which are put together by a hammer.
Thus, amino acids are the correct answer.