When Beijerinck enriched for nitrogen fixers, he inoculated soil into two types of liquid media: one containing mineral salts and mannitol but no nitrogen source (flask A), and one containing mineral salts, mannitol, and an ammonium salt (flask B). After incubation in the presence of air, what types of organisms did he expect to find in each flask?

The question is incomplete as it does not have the options which are:

A-Flask A contained ammonium utilizers, and flask B contained nitrogen fixers that could grow with or without the presence of ammonium.

B-Flask A contained nitrogen fixers that could grow both with and without ammonium; flask B did not contain nitrogen fixers but did contain organisms that could use ammonium.

C-Flask A contained nitrogen fixers that could not tolerate the presence of ammonium; flask B contained ammonium utilizers.

D-Flask A contained ammonium utilizers and flask B contained nitrogen fixers that could not tolerate the presence of ammonium.

Flask A contained nitrogen fixers that could grow both with and without ammonium; flask B did not contain nitrogen fixers but did contain organisms that

Answer:

1. Flask A - contains nitrogen fixer which could grow with or without ammonium

2. Flask B - do not contain nitrogen fixer but contains bacteria which could use the ammonium to grow.

Explanation:

In the given question, the person grew bacteria in flask A with no nitrogen and when he grew bacteria with ammonium.

He would find the nitrogen fixer in flask A as no nitrogen was provided in the medium so the bacteria could fix the atmospheric nitrogen.

The flask B could be filled with bacteria that could use the ammonium form of the nitrogen as they are supplied with the ammonium.

Thus, the selected option is correct.