17.observe the given figure carefully-
the given figures show the path of light through lenses of two different types, represented by rectangular boxes a and b.
what is the nature of lenses a and b?

12. complete each of the following word equations for synthesis reactions. a. sodium + oxygen -> b. magnesium + fluorine -> 13. complete and balance the equations for the decomposition reactions. a. hgo -> [with the triangle heat symbol above the arrow] b. h2o(l) -> [with "electricity" written above the arrow]

Which element forms an ionic bond with flourine? 1) fluorine 2) carbon 3) potassium 4) oxygen

In which environment would primary succession occur? a forest with a few remaining trees after a recent wildfire an area of exposed rock after a glacier melts away beach that is exposed to the air at low tide an abandoned baseball field in a small town