D because this is the process of when the nitrogenous bases are going to match each other to form our DNA sequence
5. System level
6. Organ level
The leaves grow when the plant is growing.and the leaves are attached because it's part of the plant
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.