Question

what is the role of blue-green algae and bacteria in increasing the fertility of soil

Answer 1

they decompose the dead organic matter that's why they are known as earth's scvangers and they dig soil turning the soil I. e. upper layer with lower layer

Answer 2

blue green algae fix the atmospheric nitrogen which increase the amount of nitrogen in soil hence fertility.
bacteria digest the waste material which act as manure.
please mark it as brainliest.