Read Philip Ball’s article focussing on the way textual cohesion is achieved through the use of words linking paragraphs logically.
http://www.nature.com/news/2001/010118/full/news010118-2.html
Do notice how a word or group of words used in the last phrase of a paragraph is reused, or a synonymous expressions, in the first sentence of the next paragraph.
Then it is up to you. What is science all about ?
Do answer using a verb in the ING form, just like in the model article and start writing. You’ll see how a word calls for others and how easy it is.
Good luck with your writing