If you look closeley at the modle you can start to notice a pattern. Therefore a repeating structure. And they arent moving freely since they are combined into a compound to create NaCi.
A) A part of biology that relates to the animal kingdom which includes their structure, ennbry----, evolution, classification habitats, etc
B) Biology that deals with trans---- or variation of inherited characteristics, like chromo---- and DNA
C) The study of embr---
(wont lemme submit bc it thinks its language)