I believe the answer is concentration
Sorry if I’m wrong hope this helps
Data:
Arsenic Molar Mass = 74,9216 ≈ 75 u (<span>atomic mass unit)</span>
Solving:
1 mole of arsenic → 75g ------------ 6,02*10²³ molecules
..................................X -------------- 1 molecule
6,02*10²³X = 75

Mary thinking her astrological sign, Leo, is a perfect fit for her personality is a belief in pseudoscience because there is not scientific evidence confirming such beliefs.
The answer is the second option.
Answer:
They all have a certain amount of protons electrons and neutrons.