Hii... I'm really struggling with this A-level biology question. I've really tried to get to the answer but I'm just not getting it.
Here's the graph and the information required:
After the 3rd injection, the concentration of anti-meningitis antibody in the blood was also measured after 60 days, after 120 days and then after 180 days. Figure 4 shows the scientists’ results. Each plotted point in Figure 4 is the result for
a different mouse
The scientists discovered that the concentration of anti-meningitis antibody of the
mouse labelled Z in Figure 4 decreased after the 3rd injection at a constant rate of 0.027 arbitrary units per day.
Use this information and Figure 4 to calculate the number of days after the 3rd injection the antibody concentration is higher than the protective antibody concentration for this mouse (2 marks).
I would really appreciate the help!