Biology 11th Edition by Gerald Audesirk,Teresa Audesirk,Bruce Byers

تمرين 6

Animals that lack a backbone are described as ______________; those that possess a backbone are ______________. The vast majority of all animals fall into which of these two groups? ______________ The only animals that lack tissues are ______________, whose bodies resemble a colony of ______________. Sea anemones and corals are ______________. Earthworms and leeches are ______________.