Answer:
486 of cell membranes
Explanation:
one cell membrane has 7*10^-9m as the height
So, by dividing 3.4 with 7*10^-9 you will get the number of cell require to form the height.
3.4/(7*10^-9)=485.71
because we can't have decimal number of cell we would round it into three significant figures, 486.
