When an ecosystem has a scarce nutrient, that is when there is a nutrient limitation. 
So the answer is C. <span>Nitrogen is typically the limiting nutrient in freshwater environments.
This is because Nitrogen is the "scarce" nutrient </span>
        
             
        
        
        
Answer : An atom with 7 protons, 6 neutrons,
and 7 electrons has an atomic mass of 13 amu.
Explanation:
As we are give that,
Number of protons
7
Number of electrons =7
Number of neutrons =6
As we know that,
Atomic number =Number of protons = Number
of electrons =7
Atomic mass = Number of neutrons + Atomic
number
Atomic mass = 6 + 7 = 13 amu
Therefore, the atomic mass is, 13 amu
        
             
        
        
        
I believe the term for an observable trait of an organism would be called or noted as the organism's phenotype.
        
             
        
        
        
Answer:
The bacteria were growing through fermentation process.
Explanation:
Cyanide have the ability to prevent the growth of microbes, and that is why it usually added to paints that want to be applied to places where the growth of microbes will be harmful to people.
The ships' hull where ballast water is been stored needed to be painted with cyanide to prevent the growth of microbes.
It should be noted that,  anaerobic microbes have the ability to reduce cyanide compound through a process known as submerged fermentation.
In the case of ships' hull, the bacteria growing on the hull were anaerobic, which means, they carried out their activities in the absence of oxygen.
 
        
             
        
        
        
Mitosis only 
OPTION A
Mitosis is simply the process of cell division.
Meiosis is the
process of producing gametes (eggs and sperm), which is important for sexual reproduction.