Answer:
It is cell, then heart tissue, heart, circulatory system and then boy.
Step-by-step explanation:
The reason of this is that the hierarchical progression of levels of biological organization corresponds to and results from the history of the development of living organisms. The accepted view of the origin of life maintains that life evolved from organic molecules which were formed independently of living organisms.
Hope this helps!
AlphaFay.
p.s I only yr 8 so haven't really learnt this.