Our cell membranes are _?

All living cells and many of the tiny organelles internal to cells are bounded by thin membranes. These membranes are composed primarily of phospholipids and proteins and are typically described as phospholipid bi-layers. ... Cell membranes also contain cholesterol in the phospholipid bilayer.

Explanation:

but there is no

i guess you forgot putting it.

answer:

sequence 1- deletion

                  2- duplication

                  3- insertion

                  4- substitute

                  5- inversion