Example: "As the best-known form of programed cell death, apoptosis is pivotal to tissue development and regeneration." This sentence is claiming that apoptosis is pivotal BECAUSE it has been studied so much (when in fact the reverse is true). Unless the paper is about the history of the human study of programmed cell death (and it wasn't), then this information is completely unnecessary.
"Apples, which come from trees, are used to make better pies than grapes." Unless the fact that apples come from trees is why they make better pies than grapes, then this information does not belong in this sentence. If it's important, put it in its own sentence. If it's not important, leave it out.
Another type of info-packing is even worse: "Ginny was the first girl to enter the classroom with pink shoes" does not mean that Ginny was the first girl to enter the classroom, only that none of the previous girls, if any, had been wearing pink shoes. "Ginny, who was wearing pink shoes, was the first girl to enter the classroom" gets this idea across. However, it implies that the fact that she was wearing pink shoes was somehow important to either why she was the first one into the classroom or to whatever had just been mentioned in previous sentences. Now replace “the first girl” with “the first study,” as I have seen so many times in research articles, be aware of its position in your sentence.