6. A relationship between 2 species, 1 species benefits and the host is harmed. a. symbiosis
b. mutualism
commensalism
d parasitism

your answer is d) paratism

Explanation:

answer: land bridge theory. land bridge theory held that shifting portions of dry land explained the finding of identical species on different continents. plate tectonic theory eventually eliminated the land bridge theory.

if the type of the food available changes, then the frequency of beak types will change, because birds with beaks more suited to the available food will be more successful over time.