I do believe the answer is A. Hope this helps.
Answer: D
Explanation:
Light waves travel in straight paths called rays. Unlike sound, where waves have to travel through matter to be heard, light waves do not have to travel through matter to be seen. Instead, rays travel in a straight path until they hit an object. A ray's straight path is the path of light
Answer:

Explanation:
Hello,
In this case, the undergoing chemical reaction is:

Thus, given the 1.00-kg of 12.5% ore, we can compute the theoretical yield of copper (II) oxide via stoichiometry:

Whereas the third factor accounts for the percent purity of the covellite. Then, given the percent yield, we can compute the actual yield by:

Regards.
The answer will be Magnesium. It is a two positive ion and it can charge electrons and protons.
Ca^2+ and I^-
Na+ and Co3^2-
Ga^3+ and ClO3
Cu^2+ and F-
NH4^- and PO4^3-
Fe2+ and (SO4)^2-
Mg2+ and NO3^-
NH4^+ and NO2^-
K^+ and (C2H3O2)^- {C2H3O2 is acetate}
Na^+ and Cr2O7^2-