Eduprobe
Question:
Which of the following features is not present in Periplaneta americana?
Schizocoelom as body cavity.
Indeterminate and radial cleavage during embryonic development.
Metamerically segmented body.
Exoskeleton composed of N-acetylglucosamine.
Solution:
The correct option is B: Indeterminate and radial cleavage during embryonic development.
Statement A is true as Periplaneta americana (arthropod) are characterized by the presence of schizocoelom, which is a body cavity directly derived from the splitting of mesoderm during embryonic development.
Statement D is true as arthropods are characterized by a segmented body with repetitive organs and tissues, i.e., metameric segmentation and jointed appendages adapted for various functions.
Statement C is true as the whole body of arthropods is covered with an exoskeleton made up of chitin, which in turn is a polymer of N-acetylglucosamine.
Statement B is false as protostomes (arthropods belong to Ecdysozoa, a group within protostomes) are characterized by spiral and determinate cleavage in which the planes of cleavage are not symmetrical between poles.