Underfull \hbox (badness 10000) in paragraph at lines

I know there are already a million posts about this problem, but I can't seem to find the problem. This little bit of text already gives me the following error: Underfull hbox (badness 10000) in paragraph in lines ... This is my text:

Cell Lines \\
In this project, there were 4 cell lines used: 2102Ep, NCCIT, NTERA-2 and T-cam2. \\
\begin{tabular}[h]{|l|l|l|}
\hline
Cell Line & Type & Origin \\
\hline
2102Ep &Embryonal Carcinoma & English\\
\hline
NCCIT & Testicular Embryonal Carcinoma & Japanese\\
\hline
NTERA-2 &Embryonal Carcinoma from metastasis: Lungs & Caucasian\\
\hline
T-cam2 & Testicular Seminoma & Japanese\\
\hline
\end{tabular}


I also have another question, how come the text is so close to the table? How can I add more space between them?

• Double backslash outside table are a bad idea in general. A common mistake made by beginners. – Johannes_B Apr 16 '18 at 11:33
• But this is what is stated in the documentation: "To start a new line without actually starting a new paragraph insert a break line point, this can be done by \\ (a double backslash as in the example)" So how should I then insert an enter in the text, according to you? – Weronika Apr 16 '18 at 13:36
• using a double backslash can be useful in text, for example if setting off a multi-line address, but in general it's a bad idea, and certainly never should be used to end a paragraph. the example you show, with a table following text, is better treated as a paragraph break, so a blank line is what should be entered. you don't identify the documentation, but from your description, it seems to not be well written (i.e. not describing "best practices"). – barbara beeton Apr 16 '18 at 14:46