Answer:
atomic mass of X is 48.0 amu
Explanation:
Let y be the atomic mass of X
Molar mass of O_2 is = 2×16 = 32 g / mol
X + O2 -----> XO_2
According to the equation ,
y g of X reacts with 32 g of O_2
24 g of X reacts with Z g of O_2
Z = ( 32×24) / y
But given that 24.0 g of X exactly reacts with 16.0 g of O_2
So Z = 16.0
⇒ (32×24) / y = 16.0
⇒ y = (32×24) / 16
y= 48.0
So atomic mass of X is 48.0 amu
I cant really help you but here is a few articles that may help you.
http://www.icr.org/article/do-bacteria-evolve-resistance-antibiotics/
https://www.ncbi.nlm.nih.gov/books/NBK45713/
http://www.windows2universe.org/cool_stuff/tour_evolution_9.html
http://evolution.berkeley.edu/evolibrary/news/080401_mrsa
http://evolution.berkeley.edu/evolibrary/article/_0/evoscales_03
The cubes have only the same volume, so the answer is c.