Hello sorry for the late replay but my best answer is going to be
A.)
Friction works in the direction opposite of motion
Answer: Genetic Variation
Explanation: It is the presence of differences in sequences of genes between individual organisms of a species.
A genotype is a genetic makeup of an organism that determines the phenotype, a characteristic that is expressed. E.g. genotype of blood type OB is made up of two alleles Io and Ib , this results in the person’s blood type to be B, the phenotype