Answer: Three samples that can be used to test for poisons are blood samples, hair samples, and gastric contents samples.
Advantages of hair samples area is that it can indicate past exposure to toxins or poisons and also provide information on how long the exposure has been going on. Poisons can sometimes be detected in hair for long periods of time. The advantages of gastric contents samples area is it shows whether the poison was digested or not. An advantage of blood samples is that it’s the most useful toxicological samples. The disadvantage of hair samples is that the results can be tainted by external sources. The disadvantage of gastric content samples is that it doesn’t always show which toxin was digested. The disadvantage of blood samples is if taken near or from the heart it may have artificially high levels of toxins that wouldn’t reflect the amount distributed throughout the body at the time of death.
Explanation:
I believe the answer is D.
Physical because it’s compound doesn’t change
Well without natural resources wood have no water, Fruits,Wood,Rocks,Air and Coal or petroleum many things we need to live.
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Answer : Note : The formula give in the question needs to be corrected , the formula of two chlorine atoms for every magnesium atom in the compound is 
which is Magnesium Chloride.
Explanation : To write the formula of the compound we need to know the charge of the atoms or elements involved in the formula.
Charge of Mg is +2 and charge of Cl is -1 , to write the formula of the compound we always criss cross the charges. And also when we write the formula the total (or net) charge of the compound should be 0. Charge of Mg is +2 so to get the total(net) charge as 0 we need two Cl atoms with each -1 charge.
Mg = +2 , Cl = -1 , Cl = -1
2 Cl = -1 + (-1) = -2
Mg = +2 and 2 Cl = -2
+2 -2 = 0
So the formula for Magnesium Chloride is
