Final answer:
Real estate professionals become members of the Texas Association of Realtors (TAR) upon joining a local association, which also affiliates them with the National Association of Realtors (NAR).
Step-by-step explanation:
When members join a local association of realtors, they automatically become members of the Texas Association of Realtors (TAR), which is a member organization of the National Association of Realtors (NAR). This structure is common in real estate associations, where membership at one level typically includes membership at state and national levels as well. By being a part of TAR, real estate professionals gain access to various resources, networking opportunities, and legislative advocacy that supports the real estate industry.