AP BIOLOGY

Detailed explanation-1: -The relative abundance of phycobilin pigments, the reddish phycoerythrin and the blue phycocyanin, explain the color of cyanobacteria. Microscopically, the blue phycocyanin pigment, the green chlorophyll, and the accessory pigments give rise to blue-green algae.

Detailed explanation-2: -Cyanobacteria, formerly known as blue-green algae, are photosynthetic microscopic organisms that are technically bacteria. They were originally called blue-green algae because dense growths often turn the water green, blue-green or brownish-green.

Detailed explanation-3: -Cyanobacteria, which are often called blue algae, can actually adopt colours ranging from green to orange via pink, depending on the dominant photosynthetic pigment in the cells of particular species.

Detailed explanation-4: -The hornwort gametophyte It may be strap-like (and branched) or grow as a rosette, depending on the genus. The thallus is typically dark green (though light green to yellowish in Notothylas) and is typically many cells thick, though the genus Dendroceros is an exception.