Histamine is found in _____.

The tricuspid valve can also be called the _____.

The tricuspid valve can also be called the _____.

Which of these fishes migrated out of freshwater and adapted to life on land?

Nearly all ________ are aquatic.

Features unique to mammals include _____.

What does the term “tetrapod” mean?

A cell membrane is

A cell membrane is

Which of these chordates is not a vertebrate?