Banded iron formations show us when volcanic activity started on earth

the oceans began forming on earth

oxygen became plentiful on earth

rocks were first formed on earth

oxygen became plentiful on earth

Explanation:

This is because banded iron formation is formed as a result of oxygen present in the ocean which is produced from cyanobacteria which undergo photosynthesis to produce carbohydrates and oxygen.

The oxygen produced are plentiful and they react with dissolved iron on the Earth's ocean to produce iron oxides which precipitated out and form a thin line floor on the ocean.

the abdomen (less formally called the belly, stomach, tummy or midriff) constitutes the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. the region occupied by the abdomen is termed the abdominal cavity. the stomach secretes acid and enzymes that digest food. ridges of muscle tissue called rugae line the stomach. the stomach muscles contract periodically, churning food to enhance digestion. the pyloric sphincter is a muscular valve that opens to allow food to pass from the stomach to the small intestine.