What do scientist use to divide the geological time scale?

This is a coral reef ecosystem. many biotic and abiotic factors affect the health of this ecosystem. which set correctly pairs a biotic factor and an abiotic factor?

1. watermelon, papaya, oranges, bananas, and lemons are included in this food group. vitamin c 2. you need 6 or more servings of this food group each day vitamins d and a 3. found in fruit and keeps blood vessels healthy calcium 4. vitamins found in milk bread and grain 5. a mineral that strengthens bones fruit

Which short-term environmental change is most likely to lead to ground shifting, landslides, and the collapse of buildings or roads? forest fires flooding earthquakes