What best describes the concept of the rock cycle

process in which : A rock forms , changes from one type of rock to another , forms again by processes on and in the Earth

thymine. in rna, thymine is replace by uracil

genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism's offspring).