Final answer:
Variable habitats tend to host species with broader ecological niches that can adapt to a range of conditions, leading to a higher number of species compared to less variable habitats.
Step-by-step explanation:
Regarding variable habitats, the correct statement is a) They host ecologically broader species than less variable habitats. Variable habitats, by nature, experience a wide range of environmental conditions. Species that thrive in these habitats tend to have broader ecological niches, allowing them to adapt to the changing conditions. As a result, they can exploit a variety of resources and survive in a more diverse range of conditions compared to species in less variable habitats. On the contrary, less variable habitats may support species that are more specialized to the stable conditions present there. Additionally, variable habitats can support a higher number of species due to the diversity of conditions and resources available.