Answer:
Natural selection 
Explanation:
Microevolution refers to changes produced at a lower level than species. In genetics, microevolution is the change in the allelic frequency perceptible in a few generations. Most of these naturally produced changes by mutation, natural selection, genetic flux, genetic drift. 
After the drought on Daphne Major, many of the plants producing small-sized seeds decreased their reproductive rate drastically. Consequently, there were almost no seeds available for the medium ground finch to feed. The population of this species also decreased to only a hundred birds over two years. Weather conditions and food availability influenced the survival of the animals. 
With time, the finched population increased again, but now, the average size of the beaks was larger. The trait modification was related to the availability of only larger seeds with thick husks. 
Eating large seeds with medium or small-sized beaks was impossible, so Finches needed to adapt, developing larger beaks to crack open the husks and eat the contents of the seeds. 
<u>Natural selection was responsible for the rapid change in the finches´ population beaks size after the drought. </u>The evolutive force modifies the allelic frequencies, increasing the frequency of genetic variants that expressed the larger beak size and declining the frequency of the alleles that expressed smaller beak size.  
 
        
             
        
        
        
This is active transport so the ions go against the concentration gradient. This means that the ions will travel from the place where there are less sodium ions(from the inside of the cell) to the place where there are more sodium ions (to the outside of the cell).
 
        
             
        
        
        
Living things go in both 
Tiger goes in consumer 
Plants goes in producer
        
             
        
        
        
The best answer would most likely be genetics or genetic theory. 
There were many doubts about Darwin's theory because Darwin could not yet describe the mechanism of inheritance. Mendel's work on inheritance was already published, 2 years earlier, but this eluded Darwin. It was only till after Darwin's death that the science of genetics came about. 
This union brought about the "modern synthesis," a theory that proposes that both genetics and natural selection is a result of evolutionary changes.