Cyanobacteria are
are eukaryotes and the earliest type of algae

Oa.
are chemoautotrophs
b.
photosynthetic bacteria
O
are the only prokaryotes that can use photosynthesis
O
not an important part of the carbon cycle
O

Photosynthetic bacteria.

Explanation:

Cyanobacteria also called Photophyta are photosynthetic bacteria even some are nitrogen-fixing bacteria. Cyanobacteria have internal membranes. These are flattened sacs called thylakoids where photosynthesis is performed.

sex cells are usually half's then they find another half and make a fertilize egg