Question

In the genus Pila, the coiling of the shell is
(a) Dextral or sinistral
(b) Dextral and sinistral
(c) Dextral
(d) sinistral

Answer 1

Hint: Chirality of the shell of gastropods is estimated by the observer while looking at the shell from the front with the spire uppermost and decided by the position of the aperture.

Complete answer:
Coiling of shell in the genus Pila can is mainly dextral type because this type of shell structure is shown by over 90% of the species of Pila while a little fraction of them show sinistral or mixed type. The shells are spirally coiled and if the coiling is anticlockwise or left-handed, it is called sinistral and if the coiling is clockwise or right-handed, the shell is called dextral. This type of coiling fashion in the shells of Pila is also called Chirality and is decided by looking at the shell from the top end. If the aperture appears to be on the left then it is sinistral otherwise dextral. The shell of an apple snail has been shown below :
The shell is a part of the body of these organisms and considered an exoskeleton that protects them from predators. It also protects from dehydration and mechanical damages.
So, the correct answer is ‘Dextral’.

Note: The shell is a calcium storage part of mollusks that also serves for the muscle attachment. These shells are studied in a branch of science called conchology whereas mollusks are studied under malacology. Some mollusks look shell-less but they are not shell-less, in such animals the shells are found in reduced form in the mantle.