Answer:
For the first box (top left one), it is AA
For the second box (top right one), it is Aa
For the third one (bottom left one), it is aA
For the fourth one (bottom right one), it is aa
This one above ^^^ is the top line of the punnet square (the small line)
A = free-hanging earlobes
a = attached earlobes
For the first box (top left one), it is free-hanging earlobes (both "A"s are dominants, and the dominant is greater than the recessive one).
For the second box (top right one), it is free-hanging earlobes (there is at least one dominant A so it will be greater than the other "a" although there is a chance for it to be an attached earlobe, but in this case, it isn't)
For the third one (bottom left one), it is free-hanging earlobes (again, there is at least one dominant A so it will be greater than the other "a" even though, there is a chance for it to be an attached earlobe, but in this case, it isn't)
For the fourth one (bottom right one), it is attached earlobes (both "a"s are recessive, there is not one dominant "a" which means that it will be an attached earlobe".
This one above is ^^^ is for the second line in the punnet square (the longest line) P.S you dont have to write the explanation you can just write if it's an attached earlobe or a free-hanging one
The ratio will be 75% to 25%. The 75% will be the offsprings inheriting the free-hanging earlobes, and the 25% will be the offsprings inheriting the attached earlobe. It is most likely that the offspring will inherit the trait for free-hanging earlobe since it is the dominant allele there is.
Hope this helped!