1 possible future is The Big Crunch. This theory assumes that the average density of the universe will be enough to stop its expansion and begin contracting.
2. Some theorists state that the expansion of the universe will go on forever, and if that happens, the universe will cool as it expands, and then it will become too cool to sustain life.
3. The Big Rip. The universe may keep expanding, as I mentioned before. But as it expands, the gravity may not be able to hold all the planets together, as it is now. Galaxies would tear apart first, followed by smaller black holes, planets and stars. Eventually, space would start expanding faster than the speed of light, and atoms would start breaking down into super small particles and everything would fall into nothing.
 
        
             
        
        
        
Answer:
Genetic drift is simply a change in the frequency of alleles in a population.
Like shown in the comic A, there are different genes present on chromosomes. All of these genes are made up of a pair of alleles. These alleles determine the genotype and the resulting phenotype of an organism.
If none of the alleles is favored by the environment, then a population will have equal no.of all the variant forms of a trait. Like shown in the comic B, both the green and the grey animals are favored equally.
 
But if natural selection occurs and one form of the allele variant is favored, then a genetic drift will occur. Most of the organisms will have the alleles which are favored by the environment. Like shown in Comic C, where the grey alleles are favored more than the green alleles.