Which cellular organelle plays a key role in apoptosis?

Here are the answers to the remaining questions:

Multiple Choice Questions:

7. B. S phase The S phase (synthesis phase) of the cell cycle is when DNA replication occurs.

8. D. On The Opposite Side Of The Body. Contralateral refers to structures located on opposite sides of the body.

9. A. Sagittal A sagittal plane divides the body vertically into right and left parts.

10. B. Interphase Interphase is the period of the cell cycle between two successive cell divisions, during which the cell grows, copies its DNA, and prepares for division.

Section B: Short answer structural questions (10 marks)

1. The correct structural order from smallest to largest is:

   $$\boxed{\text{Cell} \to \text{Tissue} \to \text{Organ} \to \text{Organism}}$$

2. Transitional epithelium is found in organs that need to stretch and recoil, such as the urinary bladder, ureters, and part of the urethra. Its importance lies in its ability to stretch and thin out when the organ fills (e.g., bladder filling with urine) and then return to its original shape, preventing rupture and leakage.

3. • Simple squamous epithelium: This tissue consists of a single layer of flattened, scale-like cells with disc-shaped central nuclei. It is very thin, allowing for rapid diffusion and filtration.
   • Simple columnar epithelium: This tissue is composed of a single layer of tall, column-shaped cells with oval nuclei usually located near the base. It is specialized for absorption and secretion, often featuring microvilli or cilia.

4. The organ system that includes the bones and cartilages is the Skeletal system. The organ system that includes the nasal cavity is the Respiratory system.