AP BIOLOGY

ANIMAL BEHAVIOR

SOCIAL BEHAVIOR

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
When oxygen was first released in the early seas, it combined with iron to form
A
RNA
B
DNA
C
protines
D
rust
Explanation: 

Detailed explanation-1: -Photosynthetic organisms were making oxygen, but it reacted with the iron dissolved in seawater to form iron oxide minerals on the ocean floor, creating banded iron formations.

Detailed explanation-2: -Most Lake Superior-type banded iron formations formed during the Paleoproterozoic, between 2.5 and 1.8 billion years ago. Prior to this, Earth’s primitive atmosphere and oceans had little or no free oxygen to react with iron, resulting in high iron concentrations in seawater.

Detailed explanation-3: -This began approximately 2.460–2.426 Ga (billion years) ago, during the Siderian period, and ended approximately 2.060 Ga, during the Rhyacian.

Detailed explanation-4: -The oxygen combined with dissolved iron in Earth’s oceans to form insoluble iron oxides, which precipitated out, forming a thin layer on the ocean floor.

Detailed explanation-5: -MIT scientists now have an answer. In a paper appearing today in Science Advances, the team reports that the Earth’s atmosphere experienced the first significant, irreversible influx of oxygen as early as 2.33 billion years ago.

There is 1 question to complete.