Create additional X axis labels without over crowding the X axis

I want to create a graph in Matlab that is similar to the one attached here and the data has been attached as 2.csv file.

I have a 2 Part query. Part 1) I am able to create an XY graph with Volume (ml) on X axis and Absorbance (mAU) on Y axis.

The attached image has been generated using Python but the problem with the graph is that the X axis is too crowded and the fraction labels (A1, A2, A3...) are not legible.

Part 2) Now I want to add labels (A1, A2, A3...) on the X axis so that they correspond to the volume on the X axis. TIA

[Joshua]

You should be able to do something like

A=importdata('2.csv')

to import the data. Then your data will be in the different columns of A which you can access by A(:,i) which is the ith column. Then plot the columns you want (for example plot(A(:,1),A(:,2))).

The text command might get you your labels:

https://www.mathworks.com/help/simulink/slref/text.html?searchHighlight=text&s_tid=doc_srchtitle