If the distribution of water is a natural monopoly, then: (i) multiple firms would likely each have to pay large fixed costs to develop their own network of pipes. (ii) allowing for competition among different firms in the water-distribution industry is efficient. (iii) a single firm can serve the market at the lowest possible average total cost.

In a unit cell of fcc structure, indicate the position of one of the tetrahedral interstitial sites by plotting the corresponding tetrahedron. do the same for one of the octahedral interstitial sites (in a separate fcc unit cell). mark the positions of all the tetrahedral and octahedral interstitial sites in the unit cells. how many equivalent tetrahedral sites and how many equivalent octahedral sites are contained in a fcc unit cell, respectively. what is the coordination number for a tetrahedral site and what is the coordination number for an octahedral site?