To solve this problem, we need to identify which feature is not present in the Phylum-Arthropoda. Let's analyze each option:$\newline \bullet$Option 1: Chitinous exoskeleton$\newline$ - Arthropods possess a hard exoskeleton made of chitin, which provides protection and support.$\newline$ - This feature is characteristic of arthropods.$\newline \bullet$Option 2: Metameric segmentation$\newline$ - Arthropods exhibit metameric segmentation, meaning their bodies are divided into segments.$\newline$ - This segmentation is evident in the division of their bodies into head, thorax, and abdomen.$\newline \bullet$Option 3: Parapodia$\newline$ - Parapodia are paired, fleshy appendages found in some annelids, such as polychaetes.$\newline$ - Arthropods do not possess parapodia.$\newline \bullet$Option 4: Jointed appendages$\newline$ - Arthropods are known for their jointed appendages, which allow for a wide range of movements.$\newline$ - This feature is a defining characteristic of the phylum.$\newline$Based on the analysis, the feature that is not present in the Phylum-Arthropoda is:$\newline$Option 3: Parapodia$\newline$Therefore, the correct answer is Option 3.