Activation of a G protein would NOT be considered signal amplification because it: a. is part of a receptor-ligand complex and diffuses to activate a single target, such as adenylyl cyclase.
b. triggers the release of intracellular ions.
c. diffuses to activate a single target, such as adenylyl cyclase.
d. is part of a receptor-ligand complex.
e. is part of a receptor-ligand complex and triggers the release of intracellular ions.

answer:

the water molecules are transferred from the roots to the stem or top parts of the tall tree because of important properties of water which are adhesion, cohesion and capillary action. cohesion is the property of water molecules keeps water molecules in a combined state by sharing of bonds between them at the atomic level. adhesion allows the interaction of water molecules with other substances or substrate. adhesion will cause the attachment of water molecules to the wall of the vessel (xylem) of the plant. capillary action occurs when the adhesive force to the vessel wall is stronger than the cohesive force between water molecules. capillary action mimics the transfer of water from a tube or pipe. in this way water utilizes its property to transfer water from down to top level of the plant.  

answer: d. load

a river's load refers to the natural phenomena in which the sediments, rocks   stones, boulders and other deposits are removed and picked from the bottom bed of the river due to the abrasion resulted by the high speed water current.