What type of spectrum uses a medium to pass through.

It won't lose or gain electrons if it's a covalent bond it shares the electrons with another atom or atoms. if it is an ionic bond it will lose the 3 electrons on the outer shell and become a positively charged ion.  credit goes to @sunshinebaby of answers.yahoo.com.

The independent variable would be the fertilizer as it is what the dependent variable (the growth of grass) depends on.

An atom's smaller negative particles are at a distance from the central positive particles, so the negative particles are easier to move. 

Answerthe distance between the two ends of the galaxy is 150,000 light years;