Question

Chalk forms from ________.

the hard parts of microscopic organisms that accumulate on the sea floor

magnesium rich fluids that chemically alter limestone bearing reefs

direct precipitation from seawater

evaporation of magnesium rich waters

Answer 1

The formation of chalk takes place when the microorganisms’ hard parts which is mainly composed of calcium carbonate gets accumulate on the sea floor and continuous accumulation of these microorganisms cause compaction and lithification of these particles and thus the formation of chalk and therefore the first option that’s the hard part of microscopic organisms that accumulated on sea floor is correct.