You are interested in studying a gene called CFTR because mutations in this gene in humans cause cystic fibrosis. You have made a line of mice that lack the mouse CFTR gene. These mice are unable to clear bacteria from their lungs, so they get lung disease. You put a normal human CFTR gene into some of these mice and discover that the mice with the human gene are able to clear bacteria from their lungs and no longer get lung disease. From this experiment, you can conclude that:

Both the mouse and human beings are encoding the proteins having similar functions.

Explanation:

The CFTR gene in the mouse and CFTR gene in the human beings encode proteins that perform similar function,this is so because if the results are same then it means that both mouse and human beings are encoding the protein that have similar function.

Option A is incorrect  because both humans and mouse are eukaryotes so they have introns and because of that even if the gene sequences are different they can still encode protein.

Option B is incorrect because  amino acid sequences can be similar inorder to have the similar function. If glutamic acid is replaced by aspartic acid, it won't have different function the function will remain same. So, identical amino acid sequences are not required. They can be similar too.

answer; both surfaces of the membrane are nonpermeable