First question: “Every system in the body relies on oxygen. From cognition to digestion, effective breathing can not only provide you with a greater sense of mental clarity, it can also help you sleep better, digest food more efficiently, improve your body's immune response, and reduce stress levels.” -google
D is your answer
hope this helps
Answer is Nitrogen, atomic number 7
The atomic number of nitrogen is 7. Hence, the number of electrons in the nitrogen atom is 7. In the nitrogen, valance electrons are 3 in number in 2P orbital. Its valency is 3. Therefore, it can make three bonds with other elements which is highest among the given options.
The answer is Law of Dominance