Final answer:
A seller benefits in intra-industry countertrade by using its existing marketing expertise and distribution networks to efficiently deal with similar products.
Step-by-step explanation:
An advantage for the seller in intra-industry countertrade is leveraging its marketing expertise and distribution networks.
Companies in similar industries benefit from specialization, and economies of scale, and are familiar with trade dynamics in their sector, which allows them to efficiently market and distribute products. A firm can apply its established know-how and resources to promote and sell traded goods, which may be similar to its offerings. Intra-industry trade fosters competition and variety, benefiting both seller and buyer through improved products and services across international borders.