This happens to me all the time.
Highlight both paragraphs and the right mouse click. Click on 'Paragraph' then tick the box 'dont add space between paragraphs'.
That should help.

I am really keen to do a PhD after I graduate next year.
However, I don't know too much about what it is really like to do a PhD.
I am a biology student interested in hole organism/ecology/behaviour.
I would like to know what the work load is like (I'm not work shy) and also how the aplication process works?
How easy (or difficult) is it to get onto a PhD.
Thanks in advance.