You prob did better than you feel as long as you didn't random guess the section. I've found B/BC to contain descriptive passages (i.e. convoluted pathways and relationships) or completely experimental - some were mixtures of these 2 types. Your goal should be to perfect a strategy appropriate for both types; to do so, start with a detailed method and do some passages slowly and carefully (w/o considering time). Figure out what helps you comprehend the passage well - if you are a visual person, make diagrams; if you are auditory, whisper quietly; if you HAVE to read twice practice skimming and rereading quickly.
Here's what helped ME:
Whenever I see a passage with no diagrams/graphs OR if it's a background paragraph to experimental passages, I get into my "concept diagram" zone. I quickly make a concept diagram made of abbreviations of molecules; horizontal arrows signify a causal/correlational (if in psych/soc section) relationship; up arrow means increase and down arrow means decrease; I would write inhibitors/stimulators abbreviation on the side - a line leading to the target molecule will contain a (+) for stimulator or (-) for inhibitor. I do this b/c I'm extremely visual and hate rereading. This also helped me accurately answer questions dealing with these aspects of a passage. This may seem time consuming but point is to practice it consistently to do it quickly. You can also practice this with intro paragraphs of research articles.
The other type of passage is experimental. Here you really have to understand the scientific method as applied to biology. This site helped me very much:
https://explorable.com/scientific-reasoning . From here, the point is not to "read" a passage - instead your main goal is to answer a few ready-made questions: what is the hypothesis/purpose? what are the independent/dependent variables?
visualize the samples (for both B/BC and P/S sections). does the graph/figure/table data agree with the hypothesis? You should be able to answer these in all the AAMC experimental passages. I know this looks like common sense, but the process of passively reading the experiment vs. actively answering these questions makes a huge difference in what you retain in your working memory. This is while doing the TIMED passage; when you review the passage, go a step further: how does the experiment give new knowledge? what are potential confounding variables? evaluate the sample: do you see any biases? internal vs. external validity? are the results still correlational or did we get closer to causation? This helped me become much more comfortable with research passages. The essential idea here is you build some mental schemas beforehand so you can conveniently store/understand all the passage info. Practice this with KA passages, EK in-class exams, and research articles.
As you do more and more passages, look for heuristics. For example, AAMC likes asking about causation; the 3 requirements for this are temporality (A causes B and not vice versa), covariance (when A changes, B changes), and lack of confounders. Then question would ask what lowers the internal validity of experiment; I've found answer choices consisting of potential confounders are most frequent. When a
serious confounder is not mentioned, you have to prove covariance: if NOT A, then not B - this simplified at least 3 such questions from AAMC FL. You should find your own heuristics.
Also, when reviewing QUESTIONS, try your best to pick apart the logic. This means simplify in as few words as possible, put question in visual form through concept diagram, etc. I found many of the subtle "logic" problems in TBR physiology much easier to answer when I put it in visual form; e.g. gaseous oxygen in lung in equilibrium w/ dissolved oxygen; then this dissolved oxygen is in equilibrium with hemoglobin and so on. The point is to use this to understand the core logic of the question. Kaplan and EK1001 bio have these sort of logic questions to practice with.
