References
https://www.nationalgeographic.com/science/article/how-many-cells-are-in-your-body
https://pubmed.ncbi.nlm.nih.gov/23829164/ 37 tril ish
https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.1002533 30 tril ish
https://www.scientificamerican.com/article/our-bodies-replace-billions-of-cells-every-day/
https://www.nature.com/articles/s41591-020-01182-9?proof=t
http://jdsjournal.com/retrieve/pii/S0923181104000982
http://scienceline.ucsb.edu/getkey.php?key=7116
Blood cells
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3678251/
https://www.mskcc.org/cancer-care/patient-education/facts-about-blood-and-blood-cells
A very interesting read from 1903
https://www.nationalgeographic.com/science/article/how-many-cells-are-in-your-body
Ear:
https://www.ncbi.nlm.nih.gov/books/NBK557588/
Brain:
https://www.sciencemag.org/news/2013/06/atomic-bombs-help-solve-brain-mystery
https://doi.org/10.1016/j.cell.2013.05.002