[lemma=surface] [□]? □
[lemma=surface] [□=□]? □
[lemma=surface] [!□]? □
The political and even personal cleavages surface then more openly . The seamless track surface also boasts banked turns to assist runners through the corners . This shows that the chemical properties of the surface also have to be complementary to each other . The arena surface also must be odor-free . Presumably , keeping one side of the brain awake allows a sleeping animal to surface occasionally to avoid drowning , explains Rattenborg . Second , projection techniques can be used to simulate environments in which any and all surfaces can potentially act like a display . The impervious surfaces significantly increase the amount and speed of the run-away water , flushing such contaminants as parking lot motor oil and lawn pesticides into rivers and streams .