Askeletal muscle twitch differs from a tetanic contraction in that

The muscle twitches are small muscle contractions that can be described as brief and fine movements. On the other hand, tetanic contraction (also called tonic contraction) is a sustained muscle contraction that can be described as prolonged and continuous. Tetanic contraction is a result of repetitive electrical stimulation of the motor unit.

the cladogram shown here shows similarities and differences among several classes of vertebrates. anatomically, the four have limb structure as their common ancestor. we might separate the mammals from the other three classes because they a) divergent; do not lay eggs b) identical; are warm-blooded c) varied; a four chambered heart d) homologous; have mammary glands