User talk:103.240.207.21

July 2020
Please refrain from making unconstructive edits to Wikipedia, as you did at Sinoatrial node. Your edits appear to constitute vandalism and have been reverted. If you would like to experiment, please use the sandbox. Repeated vandalism may result in the loss of editing privileges. Thank you. - Arjayay (talk) 10:06, 26 July 2020 (UTC)