Final answer:
The correct statement about genetic variation is that it causes gametes to have different gene arrangements than either parent, which is due to processes such as meiosis and fertilization. option a is correct.
Step-by-step explanation:
The question relates to the mechanisms of genetic variation in biological organisms. The correct statement about variation is A. Variation causes gametes to have a different arrangement of genes than either parent. This occurs as a result of several processes that increase genetic diversity, including meiosis, where homologous chromosomes segregate and chromatids can undergo crossing over; and the process of fertilization, where gametes from two different parents unite, contributing to variation in the offspring.
It's important to note that variation is not limited to few traits and is not exclusive to humans, but occurs across many species. Also, crossing over happens during meiosis, not interphase.
Each individual inherits two alleles for each gene, one from each parent, which may be the same (homozygous) or different (heterozygous), contributing to phenotype variation. The random assortment of chromosomes during meiosis, along with crossing over, results in a vast number of possible genetic combinations.
Furthermore, every person possesses a unique set of alleles due to the aforementioned genetic mechanisms, including alleles that determine blood type, such as AA, BB, AB, AO, or OO combinations. These processes ensure that each individual within a species has a distinctive and varied genetic makeup.