Can't choose my optional module in Life Sciences

It seriously depends on what you would prefer and what your priorities are! I do a similar-ish degree at a different university and I had a similar predicament in 1st year. I could've chosen an optional similar to what I was already doing or I could choose Human Endocrinology which I knew nothing about (even had to google the word lol). I went with Endocrinology and it was fun learning something new and different. I've done modules in the past where they're very similar to other content and they can get a bit boring and tedious because you already know 80% of it. However, it was harder as it was added workload learning something from complete scratch. Maybe I would've got a bit of a higher mark if I took the easier one but I dont think that was too much of a concern.

In second year I chose practicality over interest and went with an all coursework employability module because I didn't want extra exams (I prefer a balance of the two). It wasn't the most interesting thing in the world but it was an easy grade which was super helpful due to COVID haha. I don't regret my choice though it would've been nice to do a bit more of an interesting module.

So really it's up to you. Do you want to focus more on practicality than interest and go with the first module as you already know a lot of it and it's the assessment you prefer? Or do you want to focus on interest over practicality and do something new and intruiging that'll be a bit more challenging? Both ways have their merits and I don't regret doing either, but that's just my personal experience. Hope this has helped in some way!