True, a vast, flat, treeless Arctic region of Europe, Asia, and North America in which the subsoil is permanently frozen.
        
                    
             
        
        
        
Answer:
The presence of predators of deer which does not allow increase in the population of deer year after year. 
Explanation:
In an forest ecosystem, one animal controls the population of another organisms and thus there is no increase in the population of that organism and the ecosystem is in equilibrium state. The population of deer did not increase due to the presence of predators such as lion, cheetah etc and the net population is 0.
 
        
             
        
        
        
Answer:
To determine the effect of toxin binding, you perform a Competitive Binding Experiment
Explanation:
Competitive binding experiments are very relevant when matters relating to cellular and or molecular toxicity are concerned.
 They are used to determine the binding of a single concentration of labeled ligand in the presence of various concentrations of unlabeled ligand. 
They are important because:
1. Validate a direct binding assay
2. Confirm whether or not a drug binds to the receptor
3. determine and explore how low-affinity drugs and receptors interact and it's resultant effects
Cheers                                   
 
        
             
        
        
        
Answer:
That is called chicken stock
 
        
                    
             
        
        
        
Therefore, in Doppler Effect only the frequency and wavelength are changes and the wave speed does not change