老师布置的一道题,但是我不太懂,所以请哪位高手帮忙,给我引路.谢谢

It is often claimed that the Internet has created a very competitive environment in retail markets for homogeneous goods like books. However, existing empirical evidence suggests that online prices are not always lower than offline prices, and that there is persistent dispersion in prices quoted by rival online stores for the same titles.

a） In what ways can the Internet create a more competitive environment for homogeneous goods? Describe possible channels of influence and explain their likely effect on prices.

b） Provide possible explanations for the fact that online prices are sometimes higher than prices in conventional stores.

c） In theory, comparison-shopping should lead to low variation in prices amongst online retailers, but empirical evidence shows significant price dispersion. What does this finding suggest?