Howdy, no worries. I wish someone had told me many of these things while I was in the application process. That being said, student doctor network is a great forum where better minds that my own can address many of the med school-related questions you may have.
Diversity includes all of these factors. Sometimes geography is discriminated against, meaning schools like UC Riverside, which was recently created to address the medically underserved populations in the Inland Empire, are only looking for students with ties to Southern California and who intend (whether they do or not is beyond their control) to practice in the area (and hopefully as primary care physicians, who are desperately needed). Each school to some degree is unique in the applicants they accept, and this is why it’s unheard of for applicants to get accepted to every school they apply to, regardless of stats and ECs, etc.
As for the supplement, it depends on the picture you’ve already painted in your primary application. What were the main themes of your personal statement and your three most significant activities? These are the responses the committee will likely retain (I can’t expect them to remember or keep in mind all 15 activities you listed). You want to convey in the sum of your application that you are passionate about medicine (and understand what it entails), that you want to work with people/serve people and that you are an interesting, unique person. A school like Hopkins (like many) are interested in serving minorities and medically-underserved populations (they’re based in Baltimore, so of course). Depending on your other responses you want to make sure you convey the aforementioned points and reinforce them in your secondary. If you feel you didn’t address one or more of those points adequately in your primary then focus on them in the secondary. As for which activity, depending on your experiences you can make any activity reflect any values/experience depending on how you describe it. Maybe you connect life guarding with public health and how after school programs kept at-risk youth out of gangs, and created a safe environment. Just remember to write something you don’t think anyone else (or few others) will have experienced and remember that the details will make your statements memorable and will convey passion and genuineness. Needless to say this basically goes for college applications as well (different focus but same idea of hitting the major themes you want to convey about who you are as a person).
Simply put, Hopkins neuroscience is awesome. If you intend on studying any of the sciences then I don’t understand why you wouldn’t attend a research university. I have science-oriented friends who attended schools like Dartmouth or Princeton which, while phenomenal universities, have limited research opportunities. This made zero sense to me. They were competing for limited lab positions and internships and many were forced to come to schools like Hopkins during the summer for research opportunities at Hopkins or the nearby NIH facilities (I can’t even tell you how many Dartmouth students I met during the summer). Research not only reinforces what you learn in class, but it exposes you to the mindset you’ll need for any career in science and will remind you of why you were interested in science in the first place. Hands-on experience solving real-world problems while making professional connections, padding your resume, and learning current techniques using modern equipment can only be feasibly achieved while conducting research. If you don’t conduct research as an undergraduate science major you’re missing out on a big part of the experience, and Hopkins did an excellent job providing more than ample opportunities for students to get involved (besides, they require it for most majors - it’s a research-driven institution).
Beyond that, the program is well organized, flexible, staff are supportive, classes are interesting and diverse, teachers are open to new topics (we launched two new courses at student request my senior year (let alone faculty interest in starting other courses). Introductory courses are large with 100+ students (there are three intro courses you’re required to take), but once you get into your junior and senior years we had classes range from 10-25 students. Resources available to students are significant and constantly increasing (have you seen the state of the art teaching labs they recently built? Boy am I jealous). Neuroscience is a popular major offered at more and more schools, but I have yet to meet anyone else who completed a neuroscience program that has had a better experience than me while I was at Hopkins. Hopkins has its faults, but when it comes to the neuroscience program, I only have praise. The only complaints I remembering hearing were regarding how tough the program could be, then again, its neuroscience at a premier institution, what were you expecting? The other issue was the state of some of the teaching labs which were over 30 years old, but that has since been addressed with awesome new facilities.