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a) Briefly describe how minerals occur in veins and lodes
(b) Describe how coral rocks are formed

Answer Text:
a) - That is when minerals occur in crevices, crack or faults
- If they occur in small quantities in cracks or crevices then they are referred to as veins while those in large quantities are said to be in lodes
b) - Tiny marine organisms called coral polyps live in colonies in the sea
- polyps extract calcium from the sea water to make their shells
- the polyps die and their hard skeletons of calcium carbonate accumulate into solid mars
- successive colonies grow
- space between the dead corals polyps are cemented by Algae to form coral rocks