Answer:
The correct answer is: X is nitrogen dioxide, and Y is a metal oxide
Explanation:
Combustion of compound of containing nitrogen and metal will give nitrogen dioxide and metal oxide as product. During combustion reaction a compound reacts with oxygen in order to yield oxides of elements present in the compound.
The general equation is given as:

Hence, the correct answer is :X is nitrogen dioxide, and Y is a metal oxide.
Answer:
d. O2 > CoQ > FAD > NAD+
Explanation:
O2 > CoQ > FAD > NAD+
Because the reason is O2 is the last electron acceptor in the chain for a reason. FAD is also introduced later in the ETC(Electron transfer chain) than NAD+ and generates less ATP.
A is the answer
The process of forming tow DNA molecules for one is called replication