Question

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

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

Answer 1

The Correct Option is A

Option 1: Indeterminate and radial cleavage during embryonic development

Explanation:

• Indeterminate and radial cleavage during embryonic development is a feature typically found in deuterostomes (such as echinoderms and chordates), not in Periplaneta americana (a protostome). In protostomes, the cleavage is determinate and spiral, which is different from the indeterminate and radial cleavage seen in deuterostomes.
• Exoskeleton composed of N-acetylglucosamine: Periplaneta americana (the American cockroach) has an exoskeleton made of chitin, a polysaccharide that is chemically similar to N-acetylglucosamine, so this feature is present in the cockroach.
• Metamerically segmented body: Periplaneta americana exhibits metameric segmentation, meaning its body is divided into segments, a characteristic common in arthropods.
• Schizocoelom as body cavity: The body cavity of Periplaneta americana is a schizocoelom, which is typical of protostomes like arthropods. In schizocoely, the coelom forms by the splitting of mesodermal tissue.

Conclusion:

The correct answer is Option 1: Indeterminate and radial cleavage during embryonic development, as this feature is not present in Periplaneta americana.