I asked this, and didn't get a very helpful response.

Question: hi, i did this lab, from this website and I was wondering if anyone could come up with 3 sources of error, and they can't be human error. Thanks! You are saving me! Seeing as I am not allowed to post to the website :(, search on google liver lab with sand, and it is with a site called zerobio. Thanks!

Response:If you followed the directions exactly, what kind of errors could there be?

Problem: ok, well in a scientist's point of view, and from a teacher's perspective, there are always errors, and I need to come up with 6, I have 3, but I need 3 more, so any help would be great. Thanks!