Final answer:
The statement is false because tissues combine to form organs, which then form organ systems, and multiple organ systems work together to form an organism, not just tissues.
Step-by-step explanation:
The statement that multiple tissues that interact to perform a united group of functions show organization at the organismal level is false. In multicellular organisms, cells combine to form tissues, which are groups of similar cells carrying out similar functions. These tissues then combine to form organs, which are collections of tissues that work together to perform a specific function. Multiple organs then form an organ system, such as the circulatory system, which includes organs like the heart and blood vessels. Several organ systems working harmoniously together complete the functions of an independent organism.