text: i have a few questions concerning biology listed below.? symbiosis is common among prokaryotes, and probably has been for billions of years. which of the following does not represent a known prokaryotic symbiosis? a. bacteria in the human intestine produce essential vitamins b. bacteria are directly required for the pollinateion of some plants c. some prokaryotes are pathogenic d. bacteria on skin and mucous membranes can control the abundance of pathogenic microbes by outcompeting these microbes. e. nitrogen-fixing bacteria inhabit root nodules of leguminous plants  why is the filamentous morphology of the water molds considered a case of convergent evolution with the hyphae of fungi? a. filamentous body shape is evolutionarily primitive for all eukaryotes b. fungi are closely related to water molds c. hyphae and filaments are necessary for locomotion in both groups d. body shape reflects ancestor-descendant relationships amond organisms e. filamentous shape is an apadtion for a nutritional mode as a decomposer. c.  symbiosis involves a relationship by which both partners give something to the relationship.  a pathogen only takes, but does not provide.    for a,  the human intestine provides food, and the bacteria produce vitamins.  for b, the bacteria aid in pollination and once again are provided with a food source.  for d, bacteria once again have a food source (and even outcompete) and thus help provide protection.   and e, the bacteria fix nitrogen for the plants' survival and get a place to live and food.   the key to convergent evolution is that the two species are not closely related, eliminating b and d.  the process involves the independent acquiring of similar traits due to similar environmental pressures.  this points us to e.