The early atmosphere was probably mostly carbon dioxide, with little or no oxygen. <span>The proportion of oxygen went up because of </span>photosynthesis. The photosynthesis was conducted from <span>tiny organisms.
</span><span>cyanobacteria, or blue-green algae. </span><span>
They </span>used sunshine, water and carbon dioxide to produce carbohydrates and, yes, oxygen. This change to the atmosphere was very important because the <span>breathable air we enjoy today was created.</span>
Answer:
¨molecular compounds are formed by the sharing of electrons, and ionic compounds are formed by the transfer of electrons¨
Explanation:
B, Rocks are always being recycled into different forms.
6.02 times 10 to the 23 power, which is Avogadros number
