When a carboxylic is heated with an amine, it forms an amide and splits off a molecule of water. The process is called a condensation reaction.
Your compounds all contain a COOH group and an NH₂ group, so they will condense with themselves when they are strongly heated.
NH₂CH₂CH₂COOH + NH₂CH₂CH₂COOH → NH₂CH₂CH₂CO-NHCH₂CH₂COOH + H₂O
The COOH group has the highest priority in naming. An amide group is an amido substituent.
So, the name of the product is 3-(3-aminopropanamido)propanoic acid.
NH₂CH₂CH₂CH₂COOH + NH₂CH₂CH₂CH₂COOH →
NH₂CH₂CH₂CH₂CO-NHCH₂CH₂CH₂COOH + H₂O
The name of the product is 4-(4-aminobutanamido)butanoic acid.
NH₂CH₂CH₂CH₂CH₂COOH + NH₂CH₂CH₂CH₂CH₂COOH →
NH₂CH₂CH₂CH₂CH₂CO-NHCH₂CH₂CH₂CH₂COOH + H₂O
The name of the product is 5-(5-aminopentanamido)pentanoic acid.