The key is that both sections are marked as one essay together. Therefore, for part (a) you should try to focus on really close analysis of the language from the passage they give you (always go for light imagery if it's there), and then for part (b) talk about the structure, Steinbeck's intentions, context, themes, and the title if you can. As long as you have all of those parts (except for maybe the title) somewhere across both parts you'll be absolutely fine because it's all marked as one essay, so you just need to show them you can do it! Hope that helps xx