Question

Group related points.

Answer 1

1) Energy stored in coal and petroleum came from sun
- bulk of present-day supplies laid down some 200-600 million years ago
2) abundance of microscopic forms of life in tropical conditions
-Dead organisms
-Tissues recycled through scavenging and decay
3) Total decomposition of considerable dead plants and animals prevented by being covered with mud
4) Formation of rocks as the sediments hardened
5) Coal, petroleum produced by compression of matter between rocks
6) Present times, unsuitable for coal formation