The answer should be C.
In the website, the purpose of it is to promote the product, therfore, they will claim all the benefits, no matter it is true or not.
However, in a university study, the purpose is not to promote. They will make sure the test fair and reliable. They have the best equipments and tools and the top investigators.
Therfore, a university study is the best source.
Answer If a ball goes into a pocket and bounces back on to the playing surface, it is not considered pocketed. If it is the 8-ball, it is not a win. If it is the cue ball, it is not a scratch.
Explanation:
Answer : The mass of helium gas in the balloon is, 1.23 grams.
Explanation : Given,
Volume of helium gas = 6.9 L
First we have to calculate moles of helium gas at STP.
As we know that, 1 mole of substance occupy 22.4 L volume of gas.
As, 22.4 L volume of helium gas present in 1 mole of helium
So, 6.9 L volume of helium gas present in 
of helium
Now we have to calculate the mass of helium gas.
Molar mass of He gas = 4 g/mol
Thus, the mass of helium gas in the balloon is, 1.23 grams.
