The process known as differentiation
        
             
        
        
        
The correct answer is D. Digestion.
Digestion is termed as the breakdown of food which has large insoluble molecules to small soluble molecules which makes them to be absorbed in the blood plasma.
Based on the way which food is being broken, it will depend on the form of catabolism which is used in the digestion. For example, catabolism is divided into chemical and mechanical digestion where mechanical digestion breaks down large to small pieces of food. 
Those pieces of food are accessed by digestive system. In chemical digestion it is the enzymes which broke down molecules of food.
 
        
             
        
        
        
ANSWER:
The effects of increasing or decreasing the nutrient levels in an aquatic food webs is described in the explanation.
Explanation:
If the nutrient levels in an aquatic food web increase moderately then it will result in increased production of the primary producers and the consumers.
But if the nutrient levels are increased excessively, like in eutrophication, then the increased level of nutrients will result in overproduction of the consumers like fishes, etc. Hence, there will be a scarcity of resources like oxygen in the water to support them and this will lead to a decline in biodiversity of the aquatic food web.
If the nutrient levels are decreased, then there will be competition for resources among the species which will ultimately lead to the decline of some species from the aquatic food web.
 
        
             
        
        
        
Answer: It shows the distribution of the population with respect to a characteristic, quantitative and continuous, such as the weight or height of a population. It is used to determine the degree of homogeneity of the values studied, or to see the degree of variability, and therefore, the dispersion of all the values taken by the parts.
Explanation:
A histogram is a graphical representation of a variable using bars. In such a bar, <u>its area is proportional to the frequency of the values represented</u>. Thus, it shows the distribution of the population, or of the sample, with respect to a characteristic, quantitative and continuous, such as the weight or height of a population. It is used to determine the degree of homogeneity of the values studied, or to see the degree of variability, and therefore, the dispersion of all the values taken by the parts.
In order to construct a histogram first we need to have a frequency table with all the information. On the abscissa axis (horizontal axis) the intervals are placed from smallest to largest.  On the ordinate axis (vertical axis), the absolute frequencies of each of the intervals are represented.  Then, the rectangular bars of equal width are drawn, and the height represents the absolute frequency. All bars touch the bars next to each other, unless an interval has zero frequency (the height of the bar will also be zero).
<u>Thus, histograms are used to describe populations since they represent a variable and in what proportion of the population it is found.</u>