1.It leads to change in basic body design.
2.Helps in survival of species in any condition
3.results in more complex organism

1 5 1
useful variations give advantage to ondividuals in obtaining more food, reproduction, adaptation to environmental changes and higher success in the struggle of existance.
they give benifit in survival and increasing the population.
differential reproduction increases the useful variations in the populations...
other individuals with harmful variations will be destroyed........
2 5 2