Which of the following is a characteristic of all insects?

______ have highly efficient circulatory systems, and complex nervous system and sensory organs.

Bacteria reproduce by ————-

The only amphibians to entirely escape dependence on aquatic habitats are _____.

A four-chambered heart is characteristic of ______.

Single-celled photosynthetic protistans, including most of the euglenoids, chrysophytes, and dinoflagellates, are members of the _____ , the “pastures” of most aquatic habitats.

Which characteristic is NOT common to all vertebrates?

The earthworm clitellum is used to:

Organisms that can utilize reduced gases such as methane as a source of energy are

Cephalization of earthworms is an adaptation for: