▶️ Answer/Explanation
The organism shown is a scorpion, which belongs to the class Arachnida. Key identifying features include having exactly $4$ pairs of jointed walking legs (totaling $8$ legs), which distinguishes them from insects ($3$ pairs). Additionally, they possess specialized appendages called pedipalps (the pincers) and lack antennae, another hallmark of the arachnid group. Unlike crustaceans, they are primarily terrestrial and lack a heavy calcified exoskeleton with numerous pairs of legs. Their body is typically divided into two main segments: the cephalothorax and the abdomen.
✅ Answer: (A)
✅ Answer: (A)
▶️ Answer/Explanation
Organism A represents a bacterium, which is a classic example of a prokaryote. Unlike eukaryotes, prokaryotes lack a membrane-bound nucleus; instead, their genetic material consists of a circular DNA loop found in a region called the nucleoid, visible as the tangled mass in the center.
In contrast, organisms B, C, and D all contain a distinct, shaded circular structure representing a nucleus. These organisms (likely an amoeba, a flagellated protist, and a yeast or plant cell) are eukaryotes because they sequester their DNA within that nuclear envelope. Organism A also features a flagellum and a cell wall, typical of many bacterial species.
✅ Answer: (A)
▶️ Answer/Explanation
The organism is described as single-celled (unicellular) and contains a nucleus, which identifies it as a eukaryote and rules out prokaryotes. The presence of chloroplasts indicates it can perform photosynthesis, which rules out fungi. While plants have cell walls and chloroplasts, they are typically multicellular organisms. The Kingdom Protoctist serves as a diverse group that includes unicellular eukaryotic organisms that may share characteristics with plants, such as Chlorella or Euglena. Therefore, a single-celled organism with these specific eukaryotic features is classified as a protoctist.
✅ Answer: (D)
✅ Answer: (D)