Help with Grade 8 science?!?

a href="http://books.google.com/books?id=MOf_XBOr08MC&pg=PA91&lpg=PA91&dq=lack+of+salt+cause+red+blood+cells+to+swell+and+burst&source=web&ots=VMAofuXtxz&sig=7l2rfSLvFWAUZ7iOQTXxR_d5L18&hl=en&sa=X&oi=book_result&resnum=4&ct=result" rel="nofollow"http://books.google.com/books?id=MOf_XBO…/a