The genotype of an individual represents the total number and types of genes and the alleles of each gene present in the nuclei of its cells. In humans, the presence of two copies of X chromosomes makes an individual female. However, some individuals have two copies of X chromosomes but have masculine features. Similarly, some individuals have one X and one Y chromosomes in their cells. These individuals are genotypically males. But they have some feminine features. This makes them phenotypically female. Phenotype is the morphological expression of genotype.
Well, to put it to the simplest way I can get it. Protein acts as a car engine because it gives us the energy to go and do things like a car engine gives a car the will to move.
