Express in scientific notation. Choose the answer with the proper number of significant figures. 9x10^9/4.5x10^1

Which of the following is an example of a parasite?

Me i dont know what to do! the table compares the number of electrons in two unknown neutral atoms. comparison of electrons atom number of electrons a 10 d 11 use this information to determine the number of valence electrons in the atoms. which of the following correctly compares the stability of the two atoms? both are unreactive. both are highly reactive. a is unreactive and d is reactive. a is reactive and d is unreactive.

At 300 mm hg, a gas has a volume of 380 l, what is the volume at standard pressure