The Earth itself is a source of terrestrial radiation. Radioactive materials including uranium, thorium, and radium exist naturally in soil and rock. Essentially all air contains radon<span> , which is responsible for most of the dose that Americans receive each year from natural background sources.</span>
The first one might be faunal succsession and the 2nd one might be metamorphic rock
The third (left hand corner) since the x and y are both negative.
1. b
2. c
3. A. Those are the answers
The train is accelerating meaning there is a change in the velocity so the speed is either increasing or decreasing depending. The bicycle is travelling at a constant velocity meaning it is travelling at a constant speed.
