On a field trip, a student in a marine biology class collects an organism that has differentiated organs, cell walls of cellulose, and chloroplasts with chlorophyll a. based on this description, the organism could be a brown alga, a red alga, a green alga, a charophyte recently washed into the ocean from a freshwater or brackish water source, or a land plant washed into the ocean. the presence of which of the following features would definitively identify this organism as a land plant? a) alternation of generationsb) sporopolleninc) rosette cellulose-synthesizing complexesd) flagellated sperme) embryos