Which are predicted to happen in the case of a severe geomagnetic storm? Select the two correct answers. A. extra currents in the ground will disrupt power grid operations
B. signals from radio navigation systems will be disrupted and be inaccurate
C. satellites will be forced to Earth's surface
D. high-frequency radio waves used for radio communications will be blocked

when atoms of different types of elements join together, they make molecules called compounds. water consists of compound molecules made up of 2 hydrogen atoms and 1 oxygen atom. this is why it's called h2o. water will always have 2 times the number of hydrogen atoms as oxygen atoms.

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).