In addition to deep sea organisms, there are many species found throughout the ocean. The numbers and relative proportions of Bacteria and Archaea change with depth in response to changing conditions. Viruses that infect the prokaryotic organisms play a variety of important roles in this habitat, including control of their overall numbers and facilitation of horizontal gene transfer. Choose whether each statement best describes bacteria, archaea, or viruses. a. Most are inactivated by hydrolytic enzymes or sunlight,
b. Turnover in seawater is relatively rapid; the populations are replaced within a few days or weeks.
c. They are the predominant prokaryotes above 1000 m.
d. Most of these living below 1000 m are thought to be ammonia oxidizers.
e. Below 1000 m the most common phylum is Thaumarchaeota.
f. They increase to near 50% of total prokaryotes below 1000 m.
g. They are the most numerous biological entities in seawater.
h. A common genus is Pelagibacter.
i. Some types found in the photic zone carry out aerobic photosynthesis.

The different sentences that belong to different groups are given as follows:

Bacteria

A common genus is Pelagibacter.

Some types found in the photic zone carry out aerobic photosynthesis.

They are the predominant prokaryotes above 1000m

Archaea

Below 1000m the most common phylum is Thaumarchaeota.

Most of these living below 1000m are thought to be ammonia oxidizers.

They increase to near 50% of total prokaryotes below 1000m

Viruses

Most are inactivated by hydrolytic enzymes or sunlight

Turnover in sea water is relatively rapid, the populations are replaced within a few days or weeks

They are the most numerous biological entities in seawater

igneous rocks which formed by the crystallization of magma at the surface of the earth called extrusive rocks. they are characterized by fine-grained textures because the rapid cooling at or near the surface did not provide enough time for large crystals to grow.

the cover letter for a job search includes the skills one has for the particular job. including a cover letter is always a good idea, as it describes the ability to perform a task, and the employer can easily fetch the intention of the job you want to do.  

the cover letter is very important to be included in the job search document. hence, i strongly with the statement.