What prevents geologists from exploring earth's interior?

From center station, a train departs every 30 minutes on the fast line and a train departs every 50 minutes on the state line. if two trains depart from center station at 8: 00 a.m., one on each of the two lines, what is the next time that two trains, one on each line, will depart at the same time?

Describe different biomes. what are some adaptations that organisms (plants or animals) must have to live in each biome?

Idon’t quite understand this problem