Update Unit 2: Biology.md

Grade 10/Science/SNC2DZ/Unit 2: Biology.md

@@ -163,18 +163,18 @@ A person contains roughly 100 trillion cells
 
 ### Purpose 
 
-#### 1. Reproduction
+### 1. Reproduction
  - Single-cellular organisms reproduce via division **asexually**
  - Multicellular organisms reproduce via combining two germ cells ("sex cells") that contain half the DNA each of two organisms
     - This is **sexual**
 
-#### 2. Growth
+### 2. Growth
  - Cells have maximum size before transportation of substances within cell becomes **inefficient**, due to **larger cells** decreasing efficiency of `diffusion`
  - Cells transport chemicals (e.g., nutrients) via `diffusion`, this **limits cell size**
  - The only way to maintain proper function and get bigger is to **add more cells**
 
 
-#### 3. Repair
+### 3. Repair
 - **Organisms need to repair cells to stay alive and maintain proper health**
 - Millions of cells are replaced everyday
 - Cells naturally die and need to be replaced
@@ -201,7 +201,7 @@ A person contains roughly 100 trillion cells
     - Cell no longer divides ("cell cycle arrest")
     - Outside of cell cycle 
 
-#### Mitosis
+### Mitosis
 - `Chromatid`: Supercoiled DNA, only visible during mitosis, cannot be read without unwinding, similar to compressed zip file
 - `Chromosome`: Two identical "sister chromatids" held together in centre by `centromere`, or one sister chromatid after anaphase
 - `Centromere`: Proteins sticking sister chromatids
@@ -229,7 +229,7 @@ A person contains roughly 100 trillion cells
     - **Cytokinesis** usually begins in telophase
         - Cell starts to **cleave** (cell centre starts to pinch itself)
 
-#### Cytokinesis
+### Cytokinesis
  - Cell division
  - Cell splits completely to two daughter cells
  - In **animal cells**: Cell membrane pulled inward by cytoskeleton