There are both physical and biological limiting factors found in nature.
-Physical factors (abiotic factors) include temperature, water availability, oxygen, salinity, light, food and nutrients. 
-Biological factors (biotic factors) involve interactions between organisms such as predation, competition, parasitism and 
herbivory.
        
             
        
        
        
Answer:
I think the answer is determining infectivity of a virus 
Explanation:
hope that it will help you 
 
        
             
        
        
        
The answer is C. The Experiment!!!!! 
        
                    
             
        
        
        
Answer:
A. a developing nation
Explanation:
Age pyramids are the age structure diagrams that represent the number and proportion of people at each age in a population. The base of the age pyramids represents the population in pre-reproductive age which is from 0 to 10 years. The overall shape of an age pyramid indicates if the population is increasing, stationary, or shrinking. 
The age structure diagram for a developing nation has a broad base that tapers quickly towards the top. This means that a larger percentage of the population is in the pre-reproductive age group and reproductive age group with a smaller percentage of the population in the post-reproductive age. These countries have a great chance of future population growth. 
 
        
             
        
        
        
Your answer is B, cell wall.