Within a narrow range of temperatures, S. marcescens produces a red pigment called prodigiosin. Although the ultimate purpose of the pigment is a mystery, it is known that at least 10 enzymes are required for its production. If one of these enzymes is rendered nonfunctional, how would you expect the appearance of the bacteria to change?

Either the color will disappear or the brightness of the color will reduce as compared to the brightness in normal case.  

Explanation:

Non diffusible red pigment known as prodigiosin is a characteristics of S. Marcescens. Since, the red pigment is dependent on least 10 enzymes, it is clear that the pH and temperature range must be adequate for these enzymes to be functional. The optimum condition for pigment formation is 30 degree temperature and alkaline medium.

If any of the 10 enzymes become non-functional, the chances of attaining normal bright red color are not possible. Either the color will disappear or the brightness of the color will reduce as compared to the brightness in normal case.  

phylogenetic tree is the tree of life or evolution tree. it shows the different branches of evolution. the sequence goes like tissues - coelom - backbone - endoskeleton - segmentation

i believe the answer is c