diff --git a/src/exercises/easy_difficulty.rs b/src/exercises/easy_difficulty.rs
index 1366055..6bb7a52 100644
--- a/src/exercises/easy_difficulty.rs
+++ b/src/exercises/easy_difficulty.rs
@@ -46,3 +46,20 @@ where
     }
     true
 }
+
+// TODO: read about good practices when using mutable parameters
+// maybe the correct thing to do is to take an immutable one and create a copy inside the function.
+pub fn bubble_sort<T>(mut list: Vec<T>) -> Vec<T>
+where
+    T: PartialOrd,
+{
+    for lap in 1..list.len() {
+        for index in (lap..list.len()).rev() {
+            if list[index] < list[index - 1] {
+                list.swap(index, index - 1);
+            }
+        }
+    }
+
+    list
+}
diff --git a/src/exercises/mod.rs b/src/exercises/mod.rs
index 4564d48..97746d4 100644
--- a/src/exercises/mod.rs
+++ b/src/exercises/mod.rs
@@ -27,4 +27,7 @@ pub fn run_easy() {
         ),
         Err(e) => println!("Error: {}", e),
     }
+
+    let bubled_list = easy_difficulty::bubble_sort(list);
+    println!("The original list sorted is {:?}", bubled_list);
 }
diff --git a/src/functions.rs b/src/functions.rs
index d015e31..f628b52 100644
--- a/src/functions.rs
+++ b/src/functions.rs
@@ -91,4 +91,12 @@ pub fn functions_module() {
         my_point.x += x;
         my_point.y += y;
     };
+
+    // Rust provides higher order functions, such as
+    // - map : .map(|n| n * n)
+    // - filter : .filter(|&n| is_add(n))
+    // - take_while : .take_while(|&n| n < upper)
+
+    // Diverging functions
+    // Never return, marked with: !
 }
diff --git a/src/main.rs b/src/main.rs
index e92736a..2f42dd4 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -14,8 +14,8 @@
 // mod controlflow;
 // mod traits;
 // mod str_types;
-// mod functions;
-mod exercises;
+mod functions;
+// mod exercises;
 
 fn main() {
     // helloworld::hello_world_module();
@@ -27,6 +27,6 @@ fn main() {
     // controlflow::control_flow_module();
     //traits::traits_exercise();
     // str_types::str_types_module();
-    // functions::functions_module();
-    exercises::run_easy();
+    functions::functions_module();
+    // exercises::run_easy();
 }