How did trilobites contribute to the formation of dolomite and limestone

Explanation:

Over the course of millions of years they dissolve away the outer shell, sometimes replacing the molecules of exoskeleton with molecules of calcite or other minerals. In time the entire shell is replaced leaving rock in the exact shape of the trilobite. That is the fossilization process at work.

i think a) betsy can donate only blood to mark is correct because, mark and betsy have the same blood type. whereas nobody else has b+ blood so betsy can't donate to them.

1. efficient use of space

2. elimination of groundwater contamination

3. energy generation

4. lower carbon footprint