Why are producers important in a food chain or web why are they always found at the beginning of a food chain

The movement of tectonic plates in two different locations is shown below: two blocks labeled location a and location b are shown. at location a the top layer of the block shows two horizontal arrows pointing towards each other. small dunes are shown in the middle between the two arrows. the block labeled b has a vertical line in the middle. on the left of the line there is an arrow pointing down. on the right of the vertical line there is an arrow pointing up which statement is most likely true? subduction may occur in both locations. earthquakes may occur in both locations. subduction may occur in location a only and a volcanic eruption may occur in location b only. an earthquake may occur in location a only and a volcanic eruption may occur in location b only.

Epinephrine is a hormone released from the adrenal gland of the body, most often in a stressful situation. it is known as the "fight-or-flight" hormone. one way that it causes a response in the body is to activate receptors on muscle cells. where are these cellular receptors located? a. on the cell membrane b. in the nucleus c. on the cell wall d. around the mitochondria

Where does the information about where each transcription factor binds originate?