Describe the organism that scientists believe was responsible for changing the composition of the early atmosphere. what is it called and how did it change the atmosphere? why was this change to the atmosphere so important?

The early atmosphere was probably mostly carbon dioxide, with little or no oxygen. The proportion of oxygen went up because of photosynthesis. The photosynthesis was conducted from tiny organisms.
cyanobacteria, or blue-green algae. 
They used sunshine, water and carbon dioxide to produce carbohydrates and, yes, oxygen. This change to the atmosphere was very important because the breathable air we enjoy today was created.

m=9

step-by-step explanation:

7m+8=71 subtract   8 from 71 which is 63 than divide it by 7m   equal 9.

                             

The problem here is that according to aufbau principle before 3d orbital 4s subshell comes.after filling 3p orbital with electrons you have 4 electrons left, you place two in 4s with opposite spin and the other two in 3d in any of its two orbitals of total five orbitals with the same spin.