I would say B.
Explanation: Peer review improves the quality of research papers.
Oxygen is the second most abundant gas in our atmosphere.
Answer: POH=8
Explanation:PH = -log( H+concentration)
PH = 6
POH = 14 - PH = 8
The s sublevel has just one orbital, so can contain 2 electrons max. The p sublevel has 3 orbitals, so can contain 6 electrons max. The d sublevel has 5 orbitals, so can contain 10 electrons max. And the 4 sublevel has 7 orbitals, so can contain 14 electrons max.