Question 1
The modern oceans are a major repository for the greenhouse gas ________, which some organisms utilize to make their shells.
◦ CO
2◦ ammonia
◦ SiO
2◦ iron oxide
◦ limestone
Question 2
Banded Iron Formations are interbedded iron oxides and chert that formed on the sea floor between 3.5 and 2 billion years ago because ________.
◦ chert was being deposited by bacteria and iron was a common ocean deposit
◦ iron was using the oxygen produced by bacteria and chert was a common ocean deposit
◦ photosynthesis had not yet started to generate oxygen so iron and chert were deposited on the sea floor
◦ iron and chert were abundant in the early Earth
◦ outgassing produced both chert and iron oxide in roughly equal amounts
This iron bird feeder is advertised as being “squirrel-proof and bear-resistantââ
iron
iron
Iron Meteorites
The formed elements of blood.