The Mark you requested is "BIO Shirt"
In your first office action you disclaimed any exclusive right to the term "Shirt".
Understandable and correct.
But you failed to address the issue of what "BIO" means. The Examiner wants to know if "BIO" has any significance in the trade/industry for the goods/services you wish to use the mark with.
Your goods/service: 025 T-shirts, Sports Shirts;
So the Examiner issued a second office action again asking what "BIO" means (if anything).
Basically what the Examiner wants to know if the letters ‘BIO’ is an acronym or abbreviation for some term or phrase.
If you answer "BIO" is arbitrary and has no meaning, best chance for allowance.
If, for example, you answer "BIO" is an abbreviation for "BIO-HAZARD", then the Examiner will likely contend your mark is merely descriptive and refuse registration.
I do not know what "BIO" means so I cannot be very specific with my answer.
Further, be careful on this forum telling me what "BIO" means as this forum is a public forum and anyone can see your responses. Probably best not to tell me what it means unless you do not care if others see your comments.