An essential nutrient is one that a) bacteria need for proper growth and can make themselves. b) bacteria need for proper growth and cannot make themselves. c) is not needed by the bacteria for proper growth. d) is always plentiful in the environment.

The current answer is b) bacteria need for proper growth and cannot make themselves.

Explanation:

An essential nutrient is one which is required to the cell for the proper growth from the environment because it cannot be synthesized by the cell itself.

Some essential nutrients that bacteria require for their growth are carbon, nitrogen, water, iron, inorganic salts, and many other molecules.  

These nutrients should be given from an easily available source to the bacteria for their proper growth because these nutrients are required to perform essential metabolic activities and can not be synthesized by bacteria on their own.

d. making up measurements to record.

prophase: we can observe the chromosomes to coil up and condense. they become visible. nuclear membrane and envelope disintigrate.s

metaphase: chromosomes align at the center, the metaphase plate. spindle fibers attach to centromeres of the sister chromatids. they meet at kinetochores.

anaphase: sister chromatids are pulled towards each opposing centromere, set on different poles.

telophase: chromosomes are now clustered up only on either sides of the cell. nuclear membranes reform, and a new cell wall forms along the cell plate. this will lead to cytokinesis, the process that divides the cell membrane and forms the cell wall.