If all firms in an industry are price-takers, then ______.

Answer 1

then potentially a lot of things.
1) The industry is perfectly competitive (or nearly so)
2) Implying that no single firm has a "large" market share.
3) Implying that each firm in the industry produces a product that is not distinguished (different) than any other firm in the industry.

4) Alternatively, the price the firms must accept is highly regulated.

I hope this helps. Lotsa luck.