Answer:
Uniformitarianism: assumption that the same natural laws and processes that operate in our present-day scientific observations have always operated in the universe in the past and apply everywhere in the universe.
Explanation:
 
        
             
        
        
        
The answer is Observation. That's the first step. 
        
             
        
        
        
Answer:
Cross the green-pod plant with a yellow-pod plant.
Explanation:
To determine the zygosity of a particular individual, the best way is to cross it with a phenotypically recessive individual.
Such a cross in which an individual with unknown zygosity possessing a dominant trait is crossed with an individual possessing a recessive trait is termed as a test cross. 
Therefore, in the given situation the zygosity of the green pod needs to be determined and the green pod is a dominant character. Further, it is given that a yellow pod is a recessive trait, therefore a test cross can be performed between the green pod and yellow pod, and then the offsprings can be observed.
if the offsprings are all phenotypically dominant then the green pod is homozygous and if there are phenotypically recessive offspring also present then the green pod is heterozygous genotypically. 
 
        
             
        
        
        
A constant in an experiment is <u>B. </u><span><u>the quantity that must remain the same</u>. If it is constant, it doesn't change, so it cannot be variable. D makes no sense.
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