I just took a quiz on this! It's D!
Explanation:
(A)role of nittogen fixing bacteria
=Nitrogen-fixing bacteria, microorganisms capable of transforming atmospheric nitrogen into fixed nitrogen (inorganic compounds usable by plants). More than 90 percent of all nitrogen fixation is effected by these organisms, which thus play an important role in the nitrogen cycle.
B)role of nitrifying bacteria
=Nitrifying bacteria convert the most reduced form of soil nitrogen, ammonia, into its most oxidized form, nitrate. In itself, this is important for soil ecosystem function, in controlling losses of soil nitrogen through leaching and denitrification of nitrate.
C)role of denitrifying bacteria
=Denitrifying bacteria converts nitrates back to nitrogen gas.
It is a <u>mixture</u> of minerals mainly of corps that crystalizes of magma below earths surface.
I don't know sorry just google it
First we need to find the number of moles that 43.9g of gallium metal is. We can do this by finding the molar weight of gallium and cross-multiplying to cancel out units:

So we are dealing with 0.63 moles of gallium metal.
We can take from the balanced equation that 4 moles of gallium metal will react completely with 3 moles of oxygen gas. We can take this ratio and make a proportion to find the amount of oxygen gas, in moles, that will react completely with 0.63 moles of gallium metal:

Cross multiply and solve for x:


So now we know that 0.47 moles of oxygen gas will react with 43.9g of gallium metal.