Should I still take the SAT II Chem?

<p>I really dont think i know all the material to score very well on the SAT II Chemistry exam. I was wondering how, if possible, i cannot take this exam anymore. I am signed up for the SAT II World History for the same day and i want to take that exam though since i know all that material thanks to WHAP. I took the Biology SAT II last year and got a 620. Thanks!</p>