How does the writer introduce and develop the main idea of the passage?
A by comparing and contrasting different types of
talking plants and animals
B by comparing and contrasting how plants and
humans communicate
C by arguing that plants must learn several signals
D) by showing chemicals make it difficult for plants to
talk

Simba travel agency arranges trips for climbing mount kilimanjaro. for each trip, they charge an initial fee of \$100$100 in addition to a constant fee for each vertical meter climbed. for instance, the price for climbing to the shira volcanic cone, which is 30003000 meters above the base of the mountain, is \$400$400. let f(d)f(d) denote the fee of a trip ff (measured in dollars) as a function of the vertical distance climbed dd (measured in meters). write the function's formula. f(d)=