Which of the following is a defining characteristic of animals?

Which germ layer is responsible for forming the nervous system in animals?

What role do Hox genes play in organism diversification during the Cambrian period?

What role do choanocytes play in the feeding mechanism of Porifera?

Which of the following statements about Cnidarians is correct?

Which of the following statements best describes the difference between protostomes and deuterostomes in embryonic development?

The gene that encodes Retinoblastoma (Rb) protein is a conserved gene in plants and animals. This gene has the primary control over whether the cell continues to divide or to differentiate. When it is activated, Rb represses the gene required to replicate the DNA. Which of the following happens when Rb is inactivated in the stem cells of vertebrates?

Which one of the following characteristics are found in all chordates:

Lobe-finned fishes were considered to be most likely the ancestors of tetrapods. Which of the following body parts of lobe-finned fish was believed to be homologous to tetrapods?

Which of the following is not an amniote?

What evidence supports the idea that birds are descendants of theropod dinosaurs?

Which structure in the amniotic egg is primarily responsible for waste storage?