The table shows chronological events in the life of our Sun, a medium-sized star. Place the missing events into the correct rows of the table. The Sun is a white dwarf with a dim glow. A nebula located in the Milky Way galaxy begins pulling nearby hydrogen atoms into its orbit. The temperature in the core of the nebula reaches 14 million Kelvin. The Sun expands greatly and cools. It is larger and redder.

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).

true is the

before, trains worked using the steam engine. thus, it uses heat so it is crucial to apply heat balance. the steam engine absorbs energy during the stage of boiling water. so, this is the endothermic reaction. when the steam is used to work the piston, it has to release this energy through running the train. the excess energy is released as an exhaust to the chimney. this is the exothermic process because it releases energy to the surroundings.