${?}_{{?}_{{?}_{?}}{?}_{{?}_{?}}is\text{a}\text{b}\text{a}\text{r}\text{r}\text{i}\text{e}\text{r}to\text{e}\text{n}\text{t}\text{r}\text{y}\text{.}}$

${?}_{{?}_{?}}{?}_{{?}_{?}}{?}_{i}s$ a barrier $to$ entry.

Environmental uncertainty

Price reductions

Capital requirements

Advertising campaigns

Brand identification