@ onicole12901 Thank you for the suggestion. 
We do ask, and require, that an MCAT-specific source citation be included with any and all content-related suggestions, in order to streamline the process of suggestions and deck maintenance. More information and specifics can be found here, if it’s helpful: AnKing MCAT Deck Submission Guidelines
Please let me know if you have any questions.
@onicole12901, this is correct, but it may be better to rephrase as “histamine is mainly released by mast cells” because this same logic could also apply to basophils, which also release histamine