Which criteria are used to classify amphibians into orders? A. whether they reproduce sexually or asexually
B. whether they live on land or in the water
C. whether they have a backbone or not
D. whether there are legs or not, what the legs look like, and what those legs do

Vaccines are weakened forms of disease causing microorganisms, which are given to patients to prevent disease. after the vaccine is administered, the immune system responds by creating a(n) to recognize the a.) antibody, antibiotic b.) antigen, antibody c.)antibiotic, antibody d.)antibody, antigen

Agland that serves both the digestive and the endocrine systems is called

Abotanist working in the amazon rain forest discovers a new species of orchid. interestingly, males but not females of a certain wasp species keep visiting the flowers of these orchids. why?