6. Identity and explain the symbiotic relationship between the following pairs of organisas: Bacters in yogurt and the human intestinal tract

In dna, only the_ varies from one nucleotide to another. base phosphate sugar amino acid

1. seamount a raised footwall block between normal fault creates this 2. syncline break between rocks where a hanging wall rises relative to a footwall 3. hot spring on rolling hills, this a dip between hills 4. volcanic neck created when a block with hanging walls slips down between normal faults 5. caldera underwater volcano that never reaches above sea level 6. horst natural hot water on earth's surface containing many minerals 7. graben underwater volcano whose top is eroded flat by waves 8. crater less than a mile in diameter; looks like a bowl at the top of a volcano 9. guyot magma that filled the central vent that remains after the volcano has eroded 10. reverse fault over 1 mile in diameter; looks like a bowl over a volcano

Explain how paleontologists use trilobite fossils as index fossils for various geologic time periods.