1. What is an extracellular matrix? 2. What are cell junctions? 3. Mention the main differences among the following cell junctions: a. Tight junction b. Adhesion junction c. Gap junction 4. What are membrane Models? 5. Mention the main differences among the following membrane models: a. Danilli-Daveson model b. The Robertson Unit membrane Model c. The fluid-mosaic model 73 6. Wich bacteria gram positive or gram negetive bacteria is more dangerous for human health justify? 7.Differentiate b/n photosynthesis and cellular respiration?​