What is released during the formation of a peptide bond?

Find the correct option for the sequence given below:
$(1)$ Alanine $\rightarrow$ Valine
$(2)$ Asparagine $\rightarrow$ . . . . . .
$(3)$ Aspartic acid $\rightarrow$ Glutamic acid
$(4)$ Arginine $\rightarrow$ Histidine

Which of the following amino acids is acidic?

When two identical or different amino acid units join,which two groups are involved in the formation of the bond?

$A$: Tertiary structure of protein molecules makes them biologically active.
$R$: It is the native configuration of protein molecules maintained by multiple covalent bonds only.

Which of the following is consistent with the primary structure of a protein?