A polymer of amino acids is known as a protein. Proteins are fundamental components of all living organisms and perform a vast array of functions, including catalyzing metabolic reactions, DNA replication, responding to stimuli, and transporting molecules from one location to another. Amino acids, the building blocks of proteins, are linked together by peptide bonds in a specific sequence determined by genetic code. The sequence of amino acids in a protein determines its unique structure and function. Proteins can be simple or complex and are essential for the structure, function, and regulation of the body's tissues and organs. Understanding proteins and their functions is critical in fields like biochemistry, molecular biology, and medicine.

Using PVC glue on ABS (acrylonitrile butadiene styrene) is not advisable because each glue is specifically formulated for the type of plastic it's intended to fuse. PVC (polyvinyl chloride) cement creates a chemical bond by dissolving a thin layer of the surface it is applied to, allowing the pieces to essentially become one when joined. However, the chemical composition of ABS differs from PVC, meaning the PVC glue might not effectively dissolve the ABS surface for a proper bond. This can result in a weak joint prone to leaking or failure. For best results, a specialized ABS cement should be used on ABS materials, or a universal cement designed for both PVC and ABS could be employed in applications where compatibility is a concern.

A viable biodegradable alternative to polypropylene is Polylactic Acid (PLA). Derived from renewable resources like corn starch or sugar cane, PLA is known for its biodegradability under industrial composting conditions. Unlike polypropylene, which is petroleum-based and takes hundreds of years to decompose, PLA can break down into water and carbon dioxide within months under the right conditions. PLA is used in various applications, including packaging, disposable tableware, and textiles, offering a sustainable option without compromising functionality. However, it requires specific composting conditions to degrade efficiently, highlighting the importance of proper disposal to achieve its environmental benefits.