wat do u mean by slectivaely permable membrane?
Kindly refer to the following link:
https://www.meritnation.com/ask-answer/question/what-is-a-selectively-permeable-membrane/the-fundamental-unit-of-life/4868135
https://www.meritnation.com/ask-answer/question/what-is-a-selectively-permeable-membrane/the-fundamental-unit-of-life/4868135