Some photosynthetic bacteria (e. g., purple sulfur bacteria) have only photosystem i, whereas others (e. g., cyanobacteria) have both photosystem i and photosystem ii. which of the following might this observation imply?

i think a) betsy can donate only blood to mark is correct because, mark and betsy have the same blood type. whereas nobody else has b+ blood so betsy can't donate to them.

silt loam

hope this

if you listed your answers right then i believe your answer is b.