Researchers studying the rigidity and flexibility of the cell envelope used chemotaxis to measure the ability of microbes to squeeze through tight spaces. e. coli, a gram-negative bacterium, was able to traverse narrower channels than b. subtilis, a gram-positive microbe, even though both cells are the same size when grown without restriction. e. coli has the more flexible cell envelope because:_____.a. lipopolysaccharide has no charge.
b. it has fewer flagella.
c. it has only a single membrane.
d. there is less structural carbohydrate.
e. there are fewer protein receptors.