Very high-energy objects and events spit out very high-energy photons, so the instrument you need in order to detect them is the X-ray telescope. <em>(C) </em>
Inconveniently, X-ray telescopes only work when they're up in orbit, because X-rays get seriously soaked up in Earth's atmosphere, and most of them never make it down to the surface ... (lucky for us !) .
This would be more of a chemistry question. Remember magnesium has a charge of 2+, and would need to hand off its two extra electrons. Fluorine can only take one electron at a time, so there needs to be two fluorines to take one magnesium's 2 electrons.
With lithium, it has a +1 charge, so it has one extra electron, which it can hand off to just 1 fluorine atom.
Another way of looking at this is:

+ 2

= MgF2 (the charges must balance out to zero)

+

= LiF (the charges balance out to zero)
A compound. For example, hydrogen and oxygen atoms form water.
Its an electrochemical cell that derives electrical energy from spontaneous redox reactions taking place within the cell.
C. Patient info, name of med, dosage & route, special instructions, prescriber’s DEA#, and number of refills