Question

Which of the following features is not present in Periplaneta americana?

• A. Schizocoelom as body cavity
• B. Indeterminate and radial cleavage during embryonic development
• C. Exoskeleton composed of N - acetylglucosamine
• D. Metamerically segmented body

Answer 1

The correct option is B Indeterminate and radial cleavage during embryonic development

Schizocoely is the process by which some animal embryos develop, during which the body cavity (coelom) is formed by the splitting of the mesodermal embryonic tissue.
Organisms that develop through this process are called schizocoelomates. It is characteristic of protostomes (organisms in which, during embryonic development, the blastopore forms the mouth while the anus is formed later, at the opening made by the other end of the gut), examples of which include Annelids, Arthropods, and Molluscs.
Many arthropods have a chitinous exoskeleton, and chitin is a long-chain polymer of N-acetylglucosamine (a glucose derivative).
Arthropods also exhibit metameric segmentation, as seen in the cockroach.
Cleavage is the process of division of cells in the early embryo. Most protostomes exhibit determinate cleavage, in which the developmental fate of each cell is set early in the embryonic development. Indeterminate and radial cleavage are characteristic of deuterostomes (organisms in which, during embryonic development, the blastopore forms the anus), which include the higher invertebrates (Echinodermata and Hemichordata) and the chordates. Cockroaches are arthropods, which are neither chordates nor do they belong to Echinodermata or Hemichordate.