The answer would be B, George Darwin :)
They both provide a range of years of an object. I think. They’re just 2 different ways to tell the age of fossils or rocks
If we will connect the resistors 2ohms, 3ohms, 5ohms in series and the 10ohms resistance parallel then we get equivalent resistance of 5 ohms.
The equivalent circuit is,
R equivalent for the series connection is,

The equivalent resistance is 5 ohms.
So your friend is saying true.
<span>The answer is 62 u. The molecular mass of a molecule (Mr) is the sum of atomic masses (Ar) of its elements. Ar(Na) = 23 u. Ar(O) = 16 u. Therefore, the molecular mass of sodium oxide is 62 u: Mr(Na2O) = 2 * Ar(Na) + Ar(O) = 2 * 23 u + 16 u = 46 + 16 = 62 u.</span>