The answer is C blood type A has both anti-A and anti-B protein
It was used till the 1960s. Hope i helped.
Biomass decays and produces gases such as nitrogen and very small amount of helium. in many places it is used to produce energy by comustion.it's mass becomes less and a layer of humus type organic substance is left on the soil....if i'm not incorrect :)
I think the answer is Carbohydrate.
Hope this helped,have a nice day!