Final answer:
Synthetic polymers are inexpensive to produce and can be customized for a variety of applications, including durable plastics and strong materials like nylon and Kevlar.
Step-by-step explanation:
Synthetic polymers are inexpensive to make, strong and last a long time. The commercial advantages of synthetic polymers such as plastics and rubbers come from their inexpensive production costs. These polymers are not only affordable but also tailored for specific uses. Engineers can select monomer units to create polymers with desired physical properties for particular applications. For example, replacing wood with plastics has produced more durable, lighter, and easier to maintain products. Another well-known synthetic polymer is nylon, used in a wide range of products for its strength and lightness, including fabrics due to its silky fibers. Additionally, polymers like Kevlar provide exceptional strength and rigidity used in protective gear and sports equipment. Therefore, the correct answer to the student's question is cheap.