by Tim Hunt.
Dear moderator, please move this to the quiz forum.
I find it difficult to say anything other than "Those answers are not very short". You are using the question type for something it was not designed for, and that does not work very well.
If you want to manually grade long answers, why not use the Essay question type.
If you want some amount of automated grading of answers of this length, have a look at https://moodle.org/plugins/view.php?plugin=qtype_pmatch