diff --git a/Grade 10/Science/SNC2DZ/Unit 2: Biology.md b/Grade 10/Science/SNC2DZ/Unit 2: Biology.md
index 3dacf5f..ae54afa 100644
--- a/Grade 10/Science/SNC2DZ/Unit 2: Biology.md	
+++ b/Grade 10/Science/SNC2DZ/Unit 2: Biology.md	
@@ -122,9 +122,13 @@ A person contains roughly 100 trillion cells
 1. Centrioles and centrosomes
 2. Lysosomes
 
-### Centrioles and centrosomes
+### Centrosomes
  - Made of same protein as `cytoskeleton`
- - Create and manipulate spindle during mitosis in animal cells
+ - **Create and manipulate spindle* during mitosis in animal cells
+ - One centrosome is a bound pair of two `centrioles`
+    - Centrioles are present in a few types of plant cells
+    - Centrioles **create** spindle during mitosis in both plant and animal cells
+    - Centrioles do not manipulate spindle
 
 ### Lysosomes
 - Explained before.
@@ -231,12 +235,15 @@ A person contains roughly 100 trillion cells
  - In **animal cells**: Cell membrane pulled inward by cytoskeleton
  - **"Pinches in"** along equator of cell, forming **"cleavage furrow"**
  - In **plant cells**: Golgi apparatus produces and sends vesicles to centre of plant cell **"cell plate"** to make new cell wall and membrane between daughter cells
+
 ## Cell Specialization
-- `Zygote`: A single-celled organism formed from the fertilization of an egg by a sperm cell
+- `Zygote`: A single-celled organism formed from the fertilization of an egg by a sperm cell, is a totipotent stem cell
 - A cell's position in the `gastrula` (outer, middle, inner layer) will determine the fate of the cell, or its potiental. 
+- Chemical signals from other cells will also determine activated genes that lead to specialisation
 - (LOCATION LOCATION LOCAION!)
+- Specialisation is determined by reading only certain genes
 
 ### Stem Cells
 - They are an **unspecialized** cell that has the potential to become one of several types of cells. 
-- After cell division, either both can become stem cells or one stays as a stem cell and the other becomes a specialized cell
+- Can either divide to two stem cells or
 - 
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