Which theory of water transport in xylem can also be used to explain the primary movement of water in nonvascular plants such as mosses? a) cohesion-tension b] capillarity c) proton pump d) air pressure e) active transport by tracheid and vessel elements

The correct answer is: A) cohesion-tension

Water movement in xylem of plants is passive process that is driven by pressure and chemical potential gradients. Xylem is plant tissue that transports water from roots to leaves. This upward water flow (against the force of gravity) through the xylem of plants is possible because of water properties.

Cohesion refers to cohesive force between water molecules which attracts them towards each other. As a result surface tension in liquid water occurs.

Tension is the result of transpiration. Negative pressure is generated by the evaporation of water from the leaves (transpiration).  

So, transpiration pull (via capillary action and the inherent surface tension of water) is responsible for water movement upwards.  

the answer is; comparing the frequency of collisions with and without the device

this makes the anti-collision system an independent variable and the collisions a dependent variable. if there are fewer collisions with an anti-collision system that without, then it can be stated that the system is a success. essentially, collisions under an anti-collision system are compared with the frequency of collisions by cars with the human drivers.