First they look at your TOTAL GPA & TOTAL Science GPA. Then they break down your entire G.P.A. per year.
1st Year = 3.4
2nd Year = 3.5
3rd Year = 3.6
4th Year = 3.7
Total = 3.55
Also notice that in this example, there is an upward trend that also plays a role in the final decision. To what degree? Depends on the school. But you can bet your ass that having an upward trend >>>> downward trend.
However, be on the safe side and just get 4.0 throughout college 🙂