Which of these statements is NOT true about the human use of plants?

1. Most of our food ultimately comes from just a few kinds of plants.

2. Some alkaloids have important uses as medicines.

3. Wood consists of the dead cells of certain plants.

4. Poisonous plants cannot harm human.

5. Plants are the source of spices and many alcoholic drinks.

Which of the following is a mechanism of water movement in xylem that does not generate

sufficient force to explain the rise of water to the tops of the tallest tree?

1. Pressure flow hypothesis

2. Tension-cohesion

3. Root pressure

4. Active transport of potassium into guard cells

5. Transpiration