Why did robert hooke call cells cells

Hooke detailed his observations of this tiny and previously unseen world in his book, Micrographia. To him, the cork looked as if it was made of tiny pores, which he came to call “cells” because they reminded him of the cells in a monastery. ... He went on to be the first to observe and describe spermatozoa in 1677

layer 3 is younger than layer 6.

the answer is lactic acid from anaerobic respiration. the acid in lactic acid is what creates sore and burning muscles. if you think about how acid burns that will give you a clue for questions like this.