Photosynthetic prokaryotes have chlorophyll in their cytoplasm. The chlorophyll is join to protein to form chlorosome(light harvesting molecules) which in turn convert light energy to chemical energy and fixed carbon dioxide in the atmosphere by synthesizing light in sugar , thereby release oxygen to the atmosphere. The photosynthetic prokaryotes include cyanobacteria, algae e.t.c
Prokaryotes are likely to first form of life on earth and they existed billions of years ago before animals and plants.
As these prokaryotes can do photosynthesis so there most important function is produce oxygen in atmosphere for the evolution of aerobic life.
At that time the conditions were harsh on earth so these prokaryotes are used to survive under earth like in oceans. They first produce oxygen in oceans.
In eukaryotes photosynthesis emerge by endosymbiosis with photosynthetic prokaryotes.
Capillaries are one cell thick and so this makes them very thin. capillaries are also arranged in networks known as capillary beds, and thus multiple capillaries are spread over a large area.
<span>New combinations of genes may be produced by </span>immigration, mutation and sexual reproduction. These new combinations are also called variations.
