What type of monomer is used to form a dipeptide during protein synthesis

Amino acids

Explanation:

Amino acids are the building blocks of proteins. If two amino acids are joined together it will make a dipeptide.

The fish population would increase.

This is because if the number of birds decrease the number of  fishes would automatically increase as there would be less birds to eat the fishes.

According to trophic pyramid if the number of species at higher tropic level decreases the number of species at lower trophic level increases

Rest all the options has no interconnections like grass has nothing to do with the fishes and birds as well Fishes cannot occupy bird's niches because both the niches are differentThe grass and fish cannot compete for resources because their resources are different