Why do most biologists believe that true commensalism does not exist?

the relationships are probably mutual or parasitic
animals of the same species rarely compete with one another
animals of different species usually do not like to work together
an ecosystem usually has more parasites than hosts

What type of specimens where you able to see under each of the microscopes in the microscope activity

Residential construction is expanding in florida, the expansion has caused fragmentation of habitats, one of the results of the increased construction is a decrease in the number of large predators such as the coyote, black bear and pool panther, which will be the most immediate local result of this fragmentation? 1)large predators will become extinct 2)decrease in middle sized predators 3)increase in population of top carnivores 4)increase in population of prey species

26 a medida que cambia el clima, ¿qué tipo de reproducción más probablemente de a una especie mayores posibilidades de supervivencia?