Question

A crustacean with a single eye
(a) Centipede
(b) Cyclops
(c) Daphnia
(d) Both b and c

Answer 1

Hint: The subclass of subphylum mandibulata of phylum Arthropoda which contains two pairs of antennae on the cephalic region.

Complete step by step answer:
Arthropoda is the largest phylum of the animal kingdom and Insecta is the largest class in arthropods. The phylum Arthropoda is classified into 3 subphylums, they are trilobita, Chelicerata, mandibulata.
The subphylum mandibulata is further divided into 4 classes: Crustacea, Chilopoda, Diplopoda, Insecta.
Crustaceans are aquatic forms that have fused head and thorax called the cephalothorax. The sense organs include antennae, compound eyes, statocysts, etc.
Ex: daphnia, Balanus, Cyclops. Cyclops. Daphnia is characterized by the presence of a single eye.
So, the correct answer is both b and c.

Additional information:
- On earth over two-thirds of all named species belong to the phylum Arthropoda.
- They are bilaterally symmetrical, triploblastic, schizocoelomate.
- The phylum Arthropoda is subdivided into 3 subphyla: trilobite, Chelicerata, mandibulata. Sub phylum: trilobite contains extinct marine arthropods whose appendages are numerous, similar, and biramous Body is divided into 2 lateral lobes. Ex: Triarthus.
- Subphylum Chelicerata further divided into 2 classes - Xiphosura and Arachnida.
- The subphylum mandibulata is divided into 4 classes: Crustacea, Chilopoda, Diplopoda, Insecta.
- The crustacea has a unique feature i.e cephalic region pears two pairs of antennae.
- Centipedes are terrestrial air- breathing carnivorous animals belonging to the class centipedes. Not all centipedes have eyes but some of them have 200 optical lenses in compound eyes Ex: scolopendra
- Millipedes are terrestrial animals that feed on decaying plant materials. They contain 1000 legs Ex: julus.
- The most successful and largest group of animals on the earth are found in the class Insecta. The Head contains a pair of compound eyes, antennae, mandible, maxillae, and an unpaired labium. They contain 6 legs hence, they are also called Hexapoda. Ex: cockroach, butterfly.

Note: Examples of crustaceans are Palaemon(freshwater prawn), cancer(crab), balanus(rock barnacle), sacculina(root-headed barnacle), astacus(crayfish), daphnia(water flea).
Cyclops has five pairs of legs that are divided into tail-like appendages called furca.