Done.

flow-control.js

@@ -1,19 +1,49 @@
 function basicTeenager(age) {
-
+    if (age > 12 && age < 20) {
+        return "You are a teenager!"
+    }
 }
 
 function teenager(age) {
-
+    if (age > 12 && age < 20) {
+        return "You are a teenager!"
+    } else {
+        return "You are not a teenager"
+    }
 }
 
 function ageChecker(age) {
-
+    if (age > 12 && age < 20) {
+        return "You are a teenager!"
+    } else if (age < 13) {
+        return "You are a kid"
+    } else {
+        return "You are a grownup"
+    }
 }
 
 function ternaryTeenager(age) {
-
+    return (age > 12 && age < 20) ? "You are a teenager" :
+    "You are not a teenager"
 }
 
 function switchAge(age) {
-
+    switch (age) {
+        case 13:
+            return("You are a teenager")
+        case 14:
+            return("You are a teenager")
+        case 15:
+            return("You are a teenager")
+        case 16:
+            return("You are a teenager")
+        case 17:
+            return("You are a teenager")
+        case 18:
+            return("You are a teenager")
+        case 19:
+            return("You are a teenager")
+        default:
+            return("You have an age")
+    }
 }