I asked students to email me their responses. This provided me with an opportunity to send a short note back, a good way I think to start discourse and set an encouraging tone. I also got to see what students think about. I got responses that ranged from discussions of symbiosis and molecular biology to statements like "the flower is doing photosynthesis." This wasn't an examination but you could call it a probe.
Seeing, or at least thinking about what's below the surface is so much of science (and art for that matter). Considering unseen processes, engaging with thoughts about immediate and deep time, and acknowledging that what we look at has functionality beyond our simple understanding--all of these things contribute to critical thinking.
As my students spend this semester engaging abstract scientific concepts I hope they will get a sense that this frustrating process is a way of growing. As we struggle to articulate the workings of the natural world, all the way from molecules to ecosystems, I hope my students will derive enjoyment from the practice of contemplative exploration.