Lichens are among the slowest-growing organisms, but their tolerance of environmental extremes enables them to colonize habitats where few other macroscopic organisms can grow. they grow where neither the fungal partner (mycobiont) or the photosynthetic partner (photobiont) could survive alone, because they benefit from their unique symbiotic association. what mutualistic behaviors aid in the survival of both organisms?

a) the photobiont processes and provides nitrogen and carbon products to the mycobiont.
b) the photobionts are protected and able to grow in conditions in which they could not grow alone and in return release glucose in some form to the mycobiont.
c) the photobionts absorb mineral nutrients from the underlying surface or from minute traces of atmospheric contaminants while the mycobionts synthesize organic nutrients from carbon dioxide.
d) the photobionts produce ammonium and organic sodium compounds from n2 gas by sodium fixation; that in turn, aids the mycobionts in producing enzymes to decompose the substrate on which they live.