Which branch of science includes the study of black holes

What do lava flows made of aa indicate about the type of volcanic eruption that occurred? a. the eruption was viscous. b. the eruption was pyroclastic. c. the eruption was explosive. d. the eruption was quite. !

What were the main components of earth’s earliest atmosphere? oxygen and ammonia hydrogen and helium oxygen and nitrogen hydrogen and nitrogen

Johnny rode his bike 4 blicks down the street to his friend's house once he got to his friend house and realized he could not cone out to play he turned aroubd and went back home.what is displacement for the total bike ride? how did you determine this? what could we use as a reference point to determine he was in motion during his bike ride? why can you use it as a reference point