This is only explanation. What are the questions for it?
Option A and D are cell organelles. Option C is a haploid cell, while option B (bacterium) is a living organism.

<h2>Fixation</h2>
Nitrogen in its gaseous form (N2) can’t be used by most living things. It has to be converted or ‘fixed’ to a more usable form through a process called fixation. There are three ways nitrogen can be fixed to be useful for living things:
<h3>Biologically: </h3>
Nitrogen gas (N2) diffuses into the soil from the atmosphere, and species of bacteria convert this nitrogen to ammonium ions (NH4+), which can be used by plants. Legumes (such as clover and lupins) are often grown by farmers because they have nodules on their roots that contain nitrogen-fixing bacteria.
<h3>Through lightning: </h3>
Lightning converts atmospheric nitrogen into ammonia and nitrate (NO3) that enter soil with rainfall.

Nucleic acids are important because they make up genetic information in living things. There are two types of nucleic acid and they are DNA and RNA. DNA is the basic instructions for living things. It is passed down from parent to offspring and is found in thenucleus of the cell.