Internal means its on the inside
external means its on the outside
so an internal regulator is when the proteins respond to events on the inside of a cell
and an external regulator is when the proteins respond to events outside the cell
Answer:
The freshwater trout requires a lower salt ions to function.
Explanation:
I think they discovered chromosomes in DNA so that backed up his Idea
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18% of 400 is 72
Hope it helped