Final answer:
The error in the sentence is the use of 'has' instead of 'have' to match the plural subject 'people.' The correct sentence is: 'people from around the world have the opportunity to visit London's Tate Britain art gallery...'
Step-by-step explanation:
There is an error with subject-verb agreement in the provided sentence. The incorrect verb used is 'has,' which should be corrected to 'have' to properly match the plural subject 'people.'
Therefore, the corrected sentence should read, 'Thanks to a project called After Dark, which uses robots to broadcast gallery tours via a web feed, people from around the world have the opportunity to visit London's Tate Britain art gallery from the comfort of their homes.'
Subject-verb agreement is crucial in ensuring that a sentence is grammatically correct. It's important to correctly identify the subject of a sentence and match it with the appropriate verb form, singular or plural.