Which activity can reduce the amount of carbon in the atmosphere? A. recycling materials
B. building more factories that use fossil fuels
C. using petroleum-based fuel in cars
D. burning fossil fuels

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.

The first means of speeding up reactions mentioned by the speaker is raising the enzymes