In which situation does an interspecific interaction result in a positive effect on a species' growth rate, and therefore on its fitness?
a)A cowbird lays its eggs in the nests of other birds, decreasing the likelihood that all the other species' nestlings will survive.
b)A green mold destroys the fungal gardens of leaf-cutter ants.
c)Caterpillars eat many of the leaves of a plant, decreasing its rate of photosynthesis.
d)A bird distributes plant seeds via its feces, causing the seed to sprout in many new places.
e)A parasite infests a certain species of tree, causing many of the trees to die.