What definition best describes a base?

What best describes the dropping height of a ball that bounces back up to a height of 45 cm

Why did adult crab numbers decline in he ecosystem, even though sea stars were still available?

On a spring day, a middle-latitude city (about 40? north latitude) has a surface (sea-level) temperature of 10 ? c. if vertical soundings reveal a nearly constant environmental lapse rate of 6.5 ? c per kilometer and a temperature at the tropopause of –55 ? c, what is the height of the tropopause?