Profit-maximizing firms enter a competitive market when existing firms in that market have a. total revenues that exceed total variable costs. b. total revenues that exceed fixed costs. c. average total costs that are less than market price. d. average total costs that exceed average revenue.

The answer is an output contract

Answerfirst blank(more elastic); second blank(resources and firms can enter the industry);

With reference to the solutions, following things may be noted1) homogeneous solutions comprises of single phase.2) heterogeneous solution comprises of more than one phase.3) in colloidal solution, solute is evenly distributed in solvent. in such system, it is difficult to separate solute and solvent.4) in suspension, there is an uneven distribution of solute in solvent. in such system, solute and solvent gets separated on standing long.    blood is a homogeneous and colloidal solution,salad dressing is a heterogeneous and suspension solution.