Answer:
Quadrupedal refers to organisms that walk or move using four limbs. The word quadrupedal has the Latin roots "quad" meaning four and "ped" meaning foot. Bipedal refers to organisms that walk or move using two limbs. Bipedal has the Latin root "bi" meaning two, and again "ped" meaning foot.
Terrestrial and Aquatic refers to the type of organisms and their environment. Terrestrial organisms are organisms that live on dry land. Aquatic organisms are organisms that live in bodies of water, such as oceans, rivers, and lakes.
Sessile and Motile refers to mobility of organisms. Sessile organisms are organisms that aren't mobile and are fixed in place. Sessile organisms include barnacles and mature sea sponges. They attach to objects in the sea and do not move by themselves. Motile organisms are organisms that are capable of moving. Motile organisms include humans, fish, birds, etc. All these organisms have body structures (bones, muscles, nerves) that allow them to move using energy (ATP from food).
