D- Park Clean-ups is the correct answer to this question.
C)The two species cannot have viable offspring together.
An ecological niche can be defined as the functional role played by the organism or species in order to survive in it's habitat. Like the type of food consumed by the organism, type of mating mating season and others.
In the given situation, the thick beak birds likely to develop in a new species because of this typically adaptation. The two species may exhibit reproductive isolation as they may not be capable of inbreeding among themselves and cannot produce viable offspring together.
A - Herbivores
Carnivores only eat meat, Omnivores eat both, and Herbivores only eat plants.
Mutualism. e.g. oxpecker and zebra
commensalism. e.g. remora fish and sharks
parasitism. e.g. tapeworms and cow