Final answer:
The sentence with subjective language is 'This striking design was adopted out of a patriotic urge for a symbol that was uniquely Canadian.' Subjective language in historical contexts can influence perception and emotions.
Step-by-step explanation:
The sentence that uses subjective language is 'This striking design was adopted out of a patriotic urge for a symbol that was uniquely Canadian.' The word 'striking' introduces a subjective opinion because it implies that the design of the flag is impressive or draws attention, which is a matter of personal judgment. In contrast, the other sentences present objective facts about the Canadian flag and its history without expressing personal opinions or feelings.
Subjective language can influence how information is received and is often used to evoke emotional responses or persuade an audience. In the case of flags, the colors and symbols used can carry a variety of meanings and significance, deeply rooted in a nation's history and the collective experiences of its people.