diff --git a/experiment/posttest.json b/experiment/posttest.json
index ba241ed..7681a35 100644
--- a/experiment/posttest.json
+++ b/experiment/posttest.json
@@ -44,12 +44,12 @@
         "d": "Need more information"
       },
       "explanations": {
-        "a": "The right answer is (b).",
-        "b": "Correct, the right answer is (b).",
-        "c": "The right answer is (b).",
-        "d": "The right answer is (b)."
+        "a": "Correct, the right answer is (a).",
+        "b": "The right answer is (a).",
+        "c": "The right answer is (a).",
+        "d": "The right answer is (a)."
       },
-      "correctAnswer": "b",
+      "correctAnswer": "a",
       "difficulty": "intermediate"
     },
     {
@@ -70,7 +70,7 @@
       "difficulty": "advanced"
     },
     {
-      "question": "In the term ortho-graphic, ‘orthos’ means images",
+      "question": "In the term ortho-graphic, ‘orthos’ means?",
       "answers": {
         "a": "drawing",
         "b": "projection",
@@ -83,7 +83,7 @@
         "c": "Correct, The right answer is (c).",
         "d": "The right answer is (c)."
       },
-      "correctAnswer": "b",
+      "correctAnswer": "c",
       "difficulty": "advanced"
     }
   ]
diff --git a/experiment/pretest.json b/experiment/pretest.json
index 756e15f..378409f 100644
--- a/experiment/pretest.json
+++ b/experiment/pretest.json
@@ -10,12 +10,12 @@
         "d": "<img src=\"./images/image10.png\" width=80/>"
       },
       "explanations": {
-        "a": "The right answer is (b).",
-        "b": "Correct, the right answer is (b).",
-        "c": "The right answer is (b).",
-        "d": "The right answer is (b)."
+        "a": "Correct, the right answer is (a).",
+        "b": "The right answer is (a).",
+        "c": "The right answer is (a).",
+        "d": "The right answer is (a)."
       },
-      "correctAnswer": "b",
+      "correctAnswer": "a",
       "difficulty": "intermediate"
     },
     {
diff --git a/experiment/theory.md b/experiment/theory.md
index 8b063a8..dbc8e14 100644
--- a/experiment/theory.md
+++ b/experiment/theory.md
@@ -1,17 +1,11 @@
 **THEORY:**
 
-**Isometric projections** enable an object to be viewed in three dimensions in a single view, from which the actual sizes can be measured.
+**Isometric projections** is a type of technical drawing where the three axes, i.e., x, y and z, are represented at equal angles (120 degrees) to each other. This gives a three-dimensional view where an object's depth, width and height appear to be in equal proportions.
 <br>
 
 When the projectors (ex: line of sight of humans) from the source are parallel to each other and perpendicular to the plane of the object, for example a person looking at building, then the projection is called as an **Orthographic Projection**.
 
-Orthographic projection is used to represent three-dimensional
-objects into two dimension as shown in Fig 1. It is a form of parallel projection, in
-which all the projection lines are orthogonal to the projection plane,
-resulting in every plane of the scene appearing in affine transformation
-on the viewing surface. The obverse of an orthographic projection is an
-oblique projection, which is a parallel projection in which the
-projection lines are not orthogonal to the projection plane.
+Orthographic projection is a technique used to draw 3D objects on a 2D surface, as shown in Fig. 1. It involves using parallel projection lines that are perpendicular to the drawing surface. This method ensures that every part of the object is depicted in its true shape and size without any perspective distortion. In contrast, oblique projection uses projection lines that are not perpendicular to the drawing surface, leading to a distorted view of the object.
 
 <center>