What is the most likely cause of the change in life expectancy shown in the graph below?

3, a decrease in natural checks, such as disease, on the population

Explanation: If there are less diseases, then there will be less chances of catching a disease therefore resulting and a longer life expectancy and less fatalities.

I'm soooo sorry but i can't answer but you can ask another professor

By water evaporation from the leaves is created a negative pressure at the top of the tree that promotes the ascension  of the water through channels that are called xylem. there are also two molecule forces that are involved: the intra-water molecules cohesion (water molecules stick to each other) and the adhesion when the water molecules stick to the channels they are running in. this is what enables water to go from the roots to the top of a tall tree.