Nucleosynthesis began when and ended when a. the big bang occurred; the big crunch occurred b. nuclear reactions could first occur; matter had condensed into galaxies and stars c. the cosmic microwave background radiation formed; dark energy replaced it as the dominant energy form d. the universe had cooled enough for atoms to combine; protons and neutrons were too far apart to form nuclei

22. the top of a cliff is located a distance h above the ground. at a distance h/2 there is a branch that juts out from the side of the cliff, and on this branch a bird's nest is located. two children throw stones at the nest with the same initial speed, one stone straight downward from the top of the cliff and the other stone straight upward from the ground. in the absence of air resistance, which stone hits the nest in the least amount of time?