Answer:
There are three main sources of heat in the deep earth: (1) heat from when the planet formed and accreted, which has not yet been lost; (2) frictional heating, caused by denser core material sinking to the center of the planet; and (3) heat from the decay of radioactive elements.
Answer:
by watching and writing down the information that is provided
Explanation:
Answer: Ionic formula will be 
.
Explanation: 
and 
ions will form a ionic compound. Ionic compounds have both metals and non-metals.
Here is a metal and is a non-metal.
The net charge on any compound must be 0.
So we need 2 phosphate ions to balance the charge on ions. Similarly we need 3 Magnesium ions to balance the charge on ions.
Criss-crossing the charges, we will get the formula as
Criss-crossing is shown in the image below.
