They choose the topic. I'm fine with anything in biology, medicine, chemistry, and even some social science topics. Some of them run into trouble and others don't depending on what they choose.
I've considered removing the assignment a few times, but there's no skill more essential to success in science than the ability to synthesize different research articles into a coherent whole. I wouldn't feel like I was doing my job if I stopped assigning it.
I've considered removing the assignment a few times, but there's no skill more essential to success in science than the ability to synthesize different research articles into a coherent whole. I wouldn't feel like I was doing my job if I stopped assigning it.