Question

In Scaphopoda, the foot resembles which of the following?
a. Shoe-shaped
b. Hatchet-shaped
c. Dome-shaped
d. Boat-shaped

Answer 1

Hint: The scientific word, Scaphopoda refers to the foot's form resembling a ship. Scaphopods live their adult lives buried in sand or mud, with their head finish pointed down. solely the slender posterior finish of the shell sticks up into the brine for water exchange and waste expulsion.

Complete answer:
The class Scaphopoda area unit a particular cluster of molluscs ordinarily referred to as the "tusk shells" as a result of their shells area unit conelike and slightly covered to the dorsal facet, creating the shells appear as if small tusks (see the photos below). The scientific name class means "shovel foot," a term that refers to the "head" of the animal that lacks eyes and is employed for burrowing in marine mud and sediments. The foremost delicacy of scaphopods is that the hollow shell is open at each end, not only one finish as in most molluscs.

Scaphopods live their adult lives buried in sand or mud, with their head finish pointed down. solely the slender posterior finish of the shell sticks up into the brine for water exchange and waste expulsion. Gills are lost within the scaphopods, that the mantle tissue not solely produces the shell, however additionally serves the operation of gills in getting element from brine. The mantle is consolidated into a tube that surrounds the body of the animal, however it's open at each end. Water is circulated around the mantle cavity by the action of various cilia. Once the dissolved element runs low, the water is ejected through the highest finish of the shell by contraction of the foot.

Hence, the correct answer is option (D).

Note: As we know that it's created for digging, by removal the animal into the seabed. To do so, the animal pushes its floor into the bottom, anchors it by pressing blood into it so it pulls within the remainder of the shell.