Explore prompts

*(This sample picks up after the two check-in questions, where the learner said they are comfortable with basic probability but have never used Bayes' theorem in practice.)* **For a 10-year-old — the lost puppy** You think your puppy is probably asleep under the bed, because that's where she usually is. Then you hear a crunching noise from the kitchen. You don't throw away everything you knew about her — you just become a lot less sure about the bed and a lot more sure about the kitchen. *How

**Explanation** Every cell is wrapped in a thin boundary called the cell membrane. It is not a solid wall — it is more like a flexible skin with tiny gaps and doorways in it. Some things slip through those gaps on their own, and other things are too big or the wrong shape and have to be let in deliberately. That difference is the whole idea: the membrane decides what gets in and out, which is how a cell stays different on the inside from the water around it. Diffusion is the name for the "slip