Today, I  I just finished my quiz, and this time is little bit hard. So I got some questions that I want to ask you. Today's questions is  ( If the sentence is a run-on, revise it using a technique that you find effective. If the sentence is correct, do not change it. When you have finished, click on Submit both to check and to record your answer. Answers may vary. ) ( This is the sentence , The presence of a small number of white blood cells in the blood is normal, a high concentration of white cells may be cause for concern.) I don't know how to do now, can you tell me what is mean?