explain how a roller coaster functions using gravity and momentum. Why does it not need an engine or a motor to speed it up and slow it down?

In iceland, the mid atlantic ridge runs through the center of the contry. what can you conclude about the apperence of iceland many thousands of years from now?

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. !

Ineed the answer asap. in order to be considered alive, an organism must simultaneously possess the characteristics of homeostasis, heredity, cells, reproduction, and