Based on grade distributions, biology appears to be more difficult than physics when it comes to achieving the highest grades.
The reference data suggests that a smaller percentage of students achieve A* grades in biology compared to physics. While the percentage of students achieving an A grade is comparable between the two subjects, the significant difference in A* attainment points to a potential disparity in difficulty. The source data indicates that it's relatively tougher to secure top grades in Biology compared to Physics.
To summarize, while both subjects present their own challenges, the available data suggests that achieving the highest marks (A*) might be more challenging in biology than in physics.