Tiny organisms known as cyanobacteria, or blue-green algae.
Answer:
A measurement is the action of measuring something, or some amount of stuff. So it is important to measure certain things right, distance, time, and accuracy are all great things to measure. Measurements can also allow us to make desicions based on the outcome of the measurement
Fe3O4 + 4H2 = 3Fe + 4H2O
Fe3O4 + 4H2SO4 = Fe2(SO4)3 + FeSO4 + 4H2O
The answer is
D. Covalent bond
Hope this helps you have a great day.