Determine the external concentration of substance l that will result in one-half of the maximal entry rate

producers: apple trees, potatoes, carrots, grains, acorns, cabbage, grass, corn, lettuce

consumers: deer, mice, rabbits, chickens, squirrels, horses, worms, cows

predators: eagles, frogs, wolves, owls

burning fossil fouls really decrease the carbon in the atmosphere so b