B is the answer I strongly believe
The correct answer is aerobic conditions.
When you do rigorous exercise, the cells of the muscles require more oxygen and this requirement is met through aerobic conditions.
The body has its own oxygen energy system that manages the presence of the oxygen during movement.
Calvin cycle is responsible.
The four nitrogenous bases in DNA are adenine, guanine, cytosine, and thymine. They pair A-T, G-C and when transfering with RNA, A-U, which is known as Uracil, so, the pairs would be...
ATGCT
↓↓↓↓↓
UACGA
I hope this helps!
All the above is correct.