Hello!
BCA or Bachelors in Computer Application is a course that any student can do, irrespective of their background. Being a biology student will not hamper the admission process in any BCA course, but since it is a computer oriented course, he/she might face some problems that the students of commerce/computer and science/cs background do not face.
Having prior knowledge in Computer is definitely going to help, but there is nothing that dedication cannot solve. Just try to be a regular in keeping up with the topics.
Hope this helps. Feel free to ask for any other details.
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