42. which of the following is not true of a cell membrane?
cell membranes allow all substances to pass through easily
it is selectively permeable so only certain molecules can pass through it.
it is a bilayer composed mainly of phospholipids and proteins.
all of the above are true.

Astudy was interested in determining if eating milk chocolate lowered someone's cholesterol levels.ten people's cholesterol was measured. then, each of these individuals were told to eat 100g of milk chocolate every day and to eat as they normally did. after two weeks, their cholesterol levels were measured again. is there evidence to support that their cholesterol levels went down? how should we write the alternative hypothesis? (mud = the population mean difference= before - after)a. ha: mud = 0b. ha: mud > 0c. ha: mud < 0d. ha: mud does not equal 0