30 minutes or so..............
The cells in the heart need a constant supply of nutrients / oxygen and to get rid of their waste products ans that why it needs its own special circulatory system.
All of the above is your answer
Answer:
The thymus lies in the chest behind the breastbone and above the heart. Relatively large in infancy, it increases in size until puberty and thereafter shrinks to only a few grams in old age.
Explanation:
