diff --git a/_episodes/03-horizontalGeneTransfer-TDA.md b/_episodes/03-horizontalGeneTransfer-TDA.md
index d68a363..68f9074 100644
--- a/_episodes/03-horizontalGeneTransfer-TDA.md
+++ b/_episodes/03-horizontalGeneTransfer-TDA.md
@@ -419,10 +419,9 @@ strains_names
 ~~~
 {: .output}
 
-> ## Exercise 2: 
-> Apply persistent homology and plot the persistence diagram and barcode, 
-> Fill in the blanks
-> hamming_matrix_3, values, calculate_hamming_matrix, create_complex,
+> ## Exercise 2: Persistent homology of _S. agalactiae_ resistome
+> Fill in the blanks with the following parameters to calculate the persisten homology of the _S. agalactiae_ resistome
+> hamming_matrix_3, values, calculate_hamming_matrix, create_complex  
 >
 > ~~~
 > hamming_matrix_3 = __________(_____)
@@ -449,8 +448,8 @@ strains_names
 > {: .solution}
 {: .challenge}
 
-> ## Exercise 3: 
-> Apply persistent homology and plot the persistence diagram and barcode, 
+> ## Exercise 3: Plot the persistent barcode of _S. agalactiae_ resistome
+> PChose the right parameters to plot the persistence diagram of _S. agalactiae_ resistome
 > <a href="../fig/tda_04_barcode_strep.png">
 >  <img src="../fig/tda_04_barcode_strep.png" alt="Bacode population with hgt" />
 > </a>
@@ -472,6 +471,7 @@ strains_names
 > gd.plot_persistence_barcode(persistence3, legend=True)
 > ~~~
 > {: .language-python}
+> > ## Solution
 >> C)
 >> ~~~
 >> gd.plot_persistence_barcode(persistence3, legend=True)
@@ -491,6 +491,7 @@ strains_names
 > <a href="../fig/tda_04_simplicial_270.png">
 >  <img src="../fig/tda_04_simplicial_270.png" alt="Bacode population with hgt" />
 > </a>
+> > ## Solution
 >>
 >> There is a  1-holes in the barcode diagram, so there is preliminary evidence that this resistome was not acquired only vy vertical inheritance
 >> .