Yes it is C but for future reference, both A and B are referring to solids, and D is referring to a gas, hope this is helpful later!
option 2 seems appropriate for me!
They are living organisms. Not a very good question is there more to it
"The half of the Moon that points toward the Sun looks bright because it is lit by sunlight. The Moon appears to change shape because we see different amounts of the lit part as the Moon orbits Earth. ... As it moves around Earth, more and more of the lit side comes into view."
The answer is D. NADH to NAD+
When no oxygen is present, anaerobic respiration occurs.It is the only way to produce ATP in this condition.NAD+ is necessary because it is converted into NADH and at the same time ADP is converted to ATP in the reaction of pyruvate synthesis from glucose.Therefore, NADH must be converted to NAD+ in order to have NAD+ always present in the cell.
