Hi Chris!
Both BIOLOGY 225+226 and PHYSICS 235+236 are challenging classes, but it really depends on what subjects are easier for you. If memorizing concepts comes easier to you, BIOLOGY 225 might be a little less difficult, but if you’re more of a math person, PHYSICS 235 might be easier. It’s important to recognize both of these classes are rather challenging and they both require a lot of time outside of class to master the material – keep this in mind when selecting your other classes. 
Another thing to consider are the median grades for these classes. The median grade for BIOLOGY 225 is a B+, whereas the median grade for PHYSICS 235 is an A-. If taking the labs is too overwhelming at the moment, it’s very common for students to take the labs later on in their college careers, especially BIOLOGY 226. 
Another quick tip – it’s often recommend to limit yourself to 2 STEM classes per semester, just to give yourself time for other extracurriculars. Additionally, with it being your first time on campus, remember to allow yourself time to also get to explore campus. I was a transfer student myself, and my first semester was definitely a little challenging – it takes a bit of time to get used to the environment of a new city, as well as adjusting to in-person classes. 
Please let us know if you have any further questions, and feel free to stop by our advising hours on Sunday-Wednesday from 6-10pm!!
Best, 
Sara, PMH Advisor